diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ProjectWork.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ProjectWork.java
index 6c33a431f..f5403280e 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ProjectWork.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ProjectWork.java
@@ -2,9 +2,7 @@ package org.navalplanner.business.workorders.entities;
 
 import java.util.ArrayList;
 import java.util.Date;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
 import org.hibernate.validator.NotEmpty;
 import org.hibernate.validator.NotNull;
@@ -38,7 +36,7 @@ public class ProjectWork {
     // TODO turn into a many to one relationship when Customer entity is defined
     private String customer;
 
-    private Set<TaskWork> taskWorks = new HashSet<TaskWork>();
+    private List<TaskWork> taskWorks = new ArrayList<TaskWork>();
 
     public Long getId() {
         return id;
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
index 38e081806..a0ec634ea 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
@@ -1,13 +1,11 @@
 package org.navalplanner.business.workorders.entities;
 
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
 public class TaskWorkContainer extends TaskWork {
 
-    private Set<TaskWork> children = new HashSet<TaskWork>();
+    private List<TaskWork> children = new ArrayList<TaskWork>();
 
     public List<TaskWork> getChildren() {
         return new ArrayList<TaskWork>(children);
diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
index 974c7d57e..f3d732a32 100644
--- a/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
@@ -12,10 +12,11 @@
         <property name="description" access="field"></property>
         <property name="responsible" access="field"></property>
         <property name="customer" access="field"></property>
-        <set name="taskWorks" access="field" cascade="all-delete-orphan">
+        <list name="taskWorks" access="field" cascade="all-delete-orphan">
             <key column="projectId" not-null="false"></key>
+            <index column="positionInProject"></index>
             <one-to-many class="TaskWork" />
-        </set>
+        </list>
     </class>
 
     <class name="TaskWork" abstract="true">
@@ -33,10 +34,11 @@
 
         <joined-subclass name="TaskWorkContainer">
             <key column="TASKWORKID"></key>
-            <set name="children" access="field" cascade="all-delete-orphan">
+            <list name="children" access="field" cascade="all-delete-orphan">
                 <key column="parent" not-null="false"></key>
+                <index column="positionInContainer"></index>
                 <one-to-many class="TaskWork" />
-            </set>
+            </list>
         </joined-subclass>
 
         <joined-subclass name="TaskWorkLeaf">
diff --git a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/entities/ProjectWorkTest.java b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/entities/ProjectWorkTest.java
index a9ebe84c6..fa944a9fe 100644
--- a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/entities/ProjectWorkTest.java
+++ b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/entities/ProjectWorkTest.java
@@ -1,13 +1,14 @@
 package org.navalplanner.business.test.workorders.entities;
 
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.junit.Assert.assertThat;
-
 import org.junit.Test;
 import org.navalplanner.business.workorders.entities.ProjectWork;
+import org.navalplanner.business.workorders.entities.TaskWork;
 import org.navalplanner.business.workorders.entities.TaskWorkContainer;
 import org.navalplanner.business.workorders.entities.TaskWorkLeaf;
 
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+
 /**
  * Tests for {@link ProjectWork}. <br />
  * @author Óscar González Fernández <ogonzalez@igalia.com>
@@ -23,4 +24,19 @@ public class ProjectWorkTest {
         projectWork.add(container);
         assertThat(projectWork.getTaskWorks().size(), equalTo(1));
     }
+
+    @Test
+    public void testPreservesOrder() throws Exception {
+        TaskWorkContainer container = new TaskWorkContainer();
+
+        TaskWorkLeaf[] created = new TaskWorkLeaf[100];
+        for (int i = 0; i < created.length; i++) {
+            created[i] = new TaskWorkLeaf();
+            container.addTask(created[i]);
+        }
+        for (int i = 0; i < created.length; i++) {
+            assertThat(container.getChildren().get(i),
+                    equalTo((TaskWork) created[i]));
+        }
+    }
 }
diff --git a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
index 208ba0ee5..920079980 100644
--- a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
+++ b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
@@ -1,13 +1,5 @@
 package org.navalplanner.business.test.workorders.services;
 
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.hamcrest.CoreMatchers.notNullValue;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-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.List;
 
 import org.junit.Test;
@@ -28,6 +20,14 @@ import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
 
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.navalplanner.business.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_FILE;
+import static org.navalplanner.business.test.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_TEST_FILE;
+
 /**
  * Tests for {@link ProjectWork}. <br />
  * @author Óscar González Fernández <ogonzalez@igalia.com>
@@ -90,6 +90,61 @@ public class ProjectWorkServiceTest {
         assertThat(projectWorkService.find(projectWork.getId()), notNullValue());
     }
 
+    @Test
+    @NotTransactional
+    public void testOrderPreserved() throws ValidationException,
+            InstanceNotFoundException {
+        final ProjectWork projectWork = createValidProjectWork();
+        final TaskWork[] containers = new TaskWorkContainer[10];
+        for (int i = 0; i < containers.length; i++) {
+            containers[i] = new TaskWorkContainer();
+            containers[i].setName("bla");
+            projectWork.add(containers[i]);
+        }
+        TaskWorkContainer container = (TaskWorkContainer) containers[0];
+        container.setName("container");
+        final TaskWork[] tasks = new TaskWork[10];
+        for (int i = 0; i < tasks.length; i++) {
+            TaskWorkLeaf leaf = createValidLeaf("bla");
+            tasks[i] = leaf;
+            container.addTask(leaf);
+        }
+        projectWorkService.save(projectWork);
+        projectWorkService.onTransaction(new OnTransaction<Void>() {
+
+            @Override
+            public Void execute() {
+                try {
+                    ProjectWork reloaded = projectWorkService.find(projectWork
+                            .getId());
+                    List<TaskWork> taskWorks = reloaded.getTaskWorks();
+                    for (int i = 0; i < containers.length; i++) {
+                        assertThat(taskWorks.get(i).getId(),
+                                equalTo(containers[i].getId()));
+                    }
+                    TaskWorkContainer container = (TaskWorkContainer) reloaded
+                            .getTaskWorks().iterator().next();
+                    List<TaskWork> children = container.getChildren();
+                    for (int i = 0; i < tasks.length; i++) {
+                        assertThat(children.get(i).getId(), equalTo(tasks[i]
+                                .getId()));
+                    }
+                    return null;
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }
+
+        });
+        projectWorkService.remove(projectWork);
+    }
+
+    private TaskWorkLeaf createValidLeaf(String parameter) {
+        TaskWorkLeaf result = new TaskWorkLeaf();
+        result.setName(parameter);
+        return result;
+    }
+
     @Test
     @NotTransactional
     public void testAddingTaskWork() throws Exception {