diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/common/Registry.java b/navalplanner-business/src/main/java/org/navalplanner/business/common/Registry.java
index db65c558b..7a9bb9bde 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/common/Registry.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/common/Registry.java
@@ -22,6 +22,7 @@ package org.navalplanner.business.common;
 
 import org.navalplanner.business.advance.daos.IAdvanceTypeDAO;
 import org.navalplanner.business.resources.daos.ICriterionTypeDAO;
+import org.navalplanner.business.users.daos.IUserDAO;
 import org.springframework.beans.factory.annotation.Autowired;
 
 /**
@@ -43,6 +44,9 @@ public class Registry {
     @Autowired
     private ICriterionTypeDAO criterionTypeDAO;
 
+    @Autowired
+    private IUserDAO userDAO;
+
     private Registry() {
     }
 
@@ -58,4 +62,8 @@ public class Registry {
         return getInstance().criterionTypeDAO;
     }
 
+    public static IUserDAO getUserDAO() {
+        return getInstance().userDAO;
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/IUserDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/IUserDAO.java
new file mode 100644
index 000000000..5753d9d1b
--- /dev/null
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/IUserDAO.java
@@ -0,0 +1,39 @@
+/*
+ * This file is part of ###PROJECT_NAME###
+ *
+ * Copyright (C) 2009 Fundación para o Fomento da Calidade Industrial e
+ *                    Desenvolvemento Tecnolóxico de Galicia
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.navalplanner.business.users.daos;
+
+import org.navalplanner.business.common.daos.IGenericDAO;
+import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.users.entities.User;
+
+/**
+ * DAO interface for the <code>User</code> entity.
+ *
+ * @author Fernando Bellas Permuy <fbellas@udc.es>
+ */
+public interface IUserDAO extends IGenericDAO<User, Long>{
+
+    public User findByLoginName(String loginName)
+        throws InstanceNotFoundException;
+
+    public boolean exists(String loginName);
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/UserDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/UserDAO.java
new file mode 100644
index 000000000..839dead00
--- /dev/null
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/users/daos/UserDAO.java
@@ -0,0 +1,69 @@
+/*
+ * This file is part of ###PROJECT_NAME###
+ *
+ * Copyright (C) 2009 Fundación para o Fomento da Calidade Industrial e
+ *                    Desenvolvemento Tecnolóxico de Galicia
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.navalplanner.business.users.daos;
+
+import org.hibernate.Criteria;
+import org.hibernate.criterion.Restrictions;
+import org.navalplanner.business.common.daos.GenericDAOHibernate;
+import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.users.entities.User;
+import org.springframework.stereotype.Repository;
+import org.springframework.transaction.annotation.Propagation;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * Hibernate DAO for the <code>User</code> entity.
+ *
+ * @author Fernando Bellas Permuy <fbellas@udc.es>
+ */
+@Repository
+public class UserDAO extends GenericDAOHibernate<User, Long>
+    implements IUserDAO {
+
+    @Override
+    public User findByLoginName(String loginName)
+        throws InstanceNotFoundException {
+
+        Criteria c = getSession().createCriteria(User.class);
+        c.add(Restrictions.eq("loginName", loginName));
+        User user = (User) c.uniqueResult();
+
+        if (user == null) {
+            throw new InstanceNotFoundException(loginName,
+                User.class.getName());
+        } else {
+            return user;
+        }
+
+    }
+
+    @Override
+    @Transactional(readOnly = true, propagation = Propagation.REQUIRES_NEW)
+    public boolean exists(String loginName) {
+        try {
+            findByLoginName(loginName);
+            return true;
+        } catch (InstanceNotFoundException e) {
+            return false;
+        }
+    }
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/User.java b/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/User.java
new file mode 100644
index 000000000..41586a93e
--- /dev/null
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/User.java
@@ -0,0 +1,110 @@
+/*
+ * This file is part of ###PROJECT_NAME###
+ *
+ * Copyright (C) 2009 Fundación para o Fomento da Calidade Industrial e
+ *                    Desenvolvemento Tecnolóxico de Galicia
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.navalplanner.business.users.entities;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.hibernate.validator.AssertTrue;
+import org.hibernate.validator.NotEmpty;
+import org.navalplanner.business.common.BaseEntity;
+import org.navalplanner.business.common.Registry;
+import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.users.daos.IUserDAO;
+
+/**
+ * Entity for modeling a user.
+ *
+ * @author Fernando Bellas Permuy <fbellas@udc.es>
+ */
+public class User extends BaseEntity {
+
+    @NotEmpty(message="login name not specified")
+    private String loginName;
+
+    @NotEmpty(message="password not specified")
+    private String password;
+
+    @NotEmpty(message="user roles not specified")
+    private Set<UserRole> roles = new HashSet<UserRole>();
+
+    /**
+     * Necessary for Hibernate. Please, do not call it.
+     */
+    public User() {}
+
+    private User(String loginName, String password, Set<UserRole> roles) {
+        this.loginName = loginName;
+        this.password = password;
+        this.roles = roles;
+    }
+
+    public static User create(String loginName, String password,
+        Set<UserRole> roles) {
+
+        return create(new User(loginName, password, roles));
+
+    }
+
+    public String getLoginName() {
+        return loginName;
+    }
+
+    public void setLoginName(String loginName) {
+        this.loginName = loginName;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public Set<UserRole> getRoles() {
+        return roles;
+    }
+
+    public void setRoles(Set<UserRole> roles) {
+        this.roles = roles;
+    }
+
+    @AssertTrue(message="login name is already being used by another user")
+    public boolean checkConstraintUniqueLoginName() {
+
+        IUserDAO userDAO = Registry.getUserDAO();
+
+        if (isNewObject()) {
+            return !userDAO.exists(loginName);
+        } else {
+            try {
+                User u = userDAO.findByLoginName(loginName);
+                return u.getId().equals(getId());
+            } catch (InstanceNotFoundException e) {
+                return true;
+            }
+
+        }
+
+    }
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/UserRole.java b/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/UserRole.java
index 9ed363e35..d98941b3c 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/UserRole.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/users/entities/UserRole.java
@@ -29,21 +29,15 @@ import static org.navalplanner.business.i18n.I18nHelper._;
  */
 public enum UserRole {
 
-    ROLE_ADMINISTRATION("ROLE_ADMINISTRATION", _("Administration")),
-    ROLE_BASIC_USER("ROLE_BASIC_USER", _("Basic user"));
+    ROLE_BASIC_USER(_("Basic user")),
+    ROLE_ADMINISTRATION(_("Administration"));
 
-    private final String name;
     private final String displayName;
 
-    private UserRole(String name, String displayName) {
-        this.name = name;
+    private UserRole(String displayName) {
         this.displayName = displayName;
     }
 
-    public String getName() {
-        return name;
-    }
-
     public String getDisplayName() {
         return displayName;
     }
diff --git a/navalplanner-business/src/main/resources/navalplanner-business-spring-config.xml b/navalplanner-business/src/main/resources/navalplanner-business-spring-config.xml
index 17927bdac..568e70388 100644
--- a/navalplanner-business/src/main/resources/navalplanner-business-spring-config.xml
+++ b/navalplanner-business/src/main/resources/navalplanner-business-spring-config.xml
@@ -55,6 +55,9 @@
                 <value>
                     org/navalplanner/business/materials/entities/Materials.hbm.xml
                 </value>
+                <value>
+                    org/navalplanner/business/users/entities/Users.hbm.xml
+                </value>
                 </list>
         </property>
     </bean>
diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/users/entities/Users.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/users/entities/Users.hbm.xml
new file mode 100644
index 000000000..2129d2fb4
--- /dev/null
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/users/entities/Users.hbm.xml
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
+
+<hibernate-mapping package="org.navalplanner.business.users.entities"
+    default-access="field">
+
+    <!--
+        IMPORTANT: The default name for User's table ("User") is not valid
+        for some databases (e.g. PostgreSQL).
+    -->
+    <class name="User" table="NAVAL_USER">
+        <!--
+            IMPORTANT: type="long" must be specified (otherwise,
+            Hibernate infers type="integer".
+        -->
+        <id name="id" access="property" type="long">
+            <generator class="hilo">
+                <param name="max_lo">100</param>
+            </generator>
+        </id>
+        <version name="version" access="property" type="long" />
+        <property name="loginName" not-null="true" unique="true"/>
+        <property name="password" not-null="true"/>
+        <set name="roles" table="USER_ROLES">
+            <key column="userId"/>
+            <element>
+                <type name="org.hibernate.type.EnumType">
+                    <param name="enumClass">org.navalplanner.business.users.entities.UserRole</param>
+                    <!-- 12 is java.sql.Types.VARCHAR -->
+                    <param name="type">12</param>
+                </type>
+            </element>
+        </set>
+    </class>
+
+</hibernate-mapping>
diff --git a/navalplanner-business/src/test/java/org/navalplanner/business/test/users/daos/UserDAOTest.java b/navalplanner-business/src/test/java/org/navalplanner/business/test/users/daos/UserDAOTest.java
new file mode 100644
index 000000000..548364c7f
--- /dev/null
+++ b/navalplanner-business/src/test/java/org/navalplanner/business/test/users/daos/UserDAOTest.java
@@ -0,0 +1,114 @@
+/*
+ * This file is part of ###PROJECT_NAME###
+ *
+ * Copyright (C) 2009 Fundación para o Fomento da Calidade Industrial e
+ *                    Desenvolvemento Tecnolóxico de Galicia
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.navalplanner.business.test.users.daos;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+import static org.navalplanner.business.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_FILE;
+import static org.navalplanner.business.test.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_TEST_FILE;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.UUID;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.navalplanner.business.common.IAdHocTransactionService;
+import org.navalplanner.business.common.IOnTransaction;
+import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.common.exceptions.ValidationException;
+import org.navalplanner.business.users.daos.IUserDAO;
+import org.navalplanner.business.users.entities.User;
+import org.navalplanner.business.users.entities.UserRole;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.annotation.NotTransactional;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.transaction.annotation.Transactional;
+
+/**
+ * Tests for <code>IUserDAO</code>.
+ *
+ * @author Fernando Bellas Permuy <fbellas@udc.es>
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(locations = { BUSINESS_SPRING_CONFIG_FILE,
+    BUSINESS_SPRING_CONFIG_TEST_FILE })
+@Transactional
+public class UserDAOTest {
+
+    @Autowired
+    private IAdHocTransactionService transactionService;
+
+    @Autowired
+    private IUserDAO userDAO;
+
+    @Test
+    public void testBasicSave() throws InstanceNotFoundException {
+
+        User user = createUser(getUniqueName());
+
+        userDAO.save(user);
+
+        User user2 = userDAO.find(user.getId());
+        assertEquals(user, user2);
+
+    }
+
+    @Test
+    @NotTransactional
+    public void testSaveWithExistingLoginName() {
+
+        final String loginName = getUniqueName();
+
+        IOnTransaction<Void> createUser = new IOnTransaction<Void>() {
+            @Override
+            public Void execute() {
+                userDAO.save(createUser(loginName));
+                return null;
+            }
+        };
+
+        transactionService.runOnTransaction(createUser);
+
+        try {
+            transactionService.runOnTransaction(createUser);
+            fail("ValidationException expected");
+        } catch (ValidationException e) {
+        }
+
+    }
+
+    private String getUniqueName() {
+        return UUID.randomUUID().toString();
+    }
+
+    private User createUser(String loginName) {
+
+        Set<UserRole> roles = new HashSet<UserRole>();
+        roles.add(UserRole.ROLE_BASIC_USER);
+        roles.add(UserRole.ROLE_ADMINISTRATION);
+
+        return User.create(loginName, "XXX", roles);
+
+    }
+
+}
diff --git a/navalplanner-business/src/test/resources/navalplanner-business-spring-config-test.xml b/navalplanner-business/src/test/resources/navalplanner-business-spring-config-test.xml
index e6f947c0a..522a2ced4 100644
--- a/navalplanner-business/src/test/resources/navalplanner-business-spring-config-test.xml
+++ b/navalplanner-business/src/test/resources/navalplanner-business-spring-config-test.xml
@@ -63,6 +63,9 @@
                 <value>
                     org/navalplanner/business/materials/entities/Materials.hbm.xml
                 </value>
+                <value>
+                    org/navalplanner/business/users/entities/Users.hbm.xml
+                </value>
                 <value>
                     TestEntities.hbm.xml
                 </value>
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/security/SecurityUtils.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/security/SecurityUtils.java
index 604bec99e..084cca713 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/security/SecurityUtils.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/security/SecurityUtils.java
@@ -33,7 +33,7 @@ public final class SecurityUtils {
     private SecurityUtils() {}
 
     public final static boolean isUserInRole(UserRole role) {
-        return Executions.getCurrent().isUserInRole(role.getName());
+        return Executions.getCurrent().isUserInRole(role.name());
     }
 
 }