diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/common/exceptions/ValidationException.java b/navalplanner-business/src/main/java/org/navalplanner/business/common/exceptions/ValidationException.java
index ba470e723..b5e1b1671 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/common/exceptions/ValidationException.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/common/exceptions/ValidationException.java
@@ -28,6 +28,7 @@ import org.navalplanner.business.common.BaseEntity;
 /**
  * Encapsulates some validation failure <br />
  * @author Óscar González Fernández <ogonzalez@igalia.com>
+ * @author Diego Pino García <dpino@igalia.com>
  */
 public class ValidationException extends RuntimeException {
 
@@ -63,6 +64,12 @@ public class ValidationException extends RuntimeException {
         return bean.toString();
     }
 
+    public static ValidationException invalidValue(String message, Object value) {
+        InvalidValue invalidValue = new InvalidValue(message, null, "", value,
+                null);
+        return new ValidationException(invalidValue);
+    }
+
     private InvalidValue[] invalidValues;
 
     public InvalidValue[] getInvalidValues() {
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/costcategories/entities/CostCategory.java b/navalplanner-business/src/main/java/org/navalplanner/business/costcategories/entities/CostCategory.java
index 3089e1c52..8f18bab12 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/costcategories/entities/CostCategory.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/costcategories/entities/CostCategory.java
@@ -45,6 +45,7 @@ import org.navalplanner.business.costcategories.daos.ICostCategoryDAO;
 
 /**
  * @author Jacobo Aragunde Perez <jaragunde@igalia.com>
+ * @author Diego Pino García <dpino@igalia.com>
  */
 public class CostCategory extends IntegrationEntity {
 
@@ -91,6 +92,58 @@ public class CostCategory extends IntegrationEntity {
         return (CostCategory) create(new CostCategory(name));
     }
 
+    public static void validateHourCostsOverlap(Set<HourCost> hoursCosts)
+            throws ValidationException {
+        List<HourCost> listHourCosts = new ArrayList<HourCost>(hoursCosts);
+        for (int i = 0; i < listHourCosts.size(); i++) {
+            LocalDate initDate = listHourCosts.get(i).getInitDate();
+            LocalDate endDate = listHourCosts.get(i).getEndDate();
+            for (int j = i + 1; j < listHourCosts.size(); j++) {
+                HourCost listElement = listHourCosts.get(j);
+                if (listElement.getType() == null
+                        || listHourCosts.get(i).getType() == null) {
+                    // this is not exactly an overlapping but a
+                    // problem with missing compulsory fields
+                    throw ValidationException.invalidValue(
+                            _("Hours cost type cannot be empty or null"),
+                            listElement);
+                }
+                if (listElement.getType().getId()
+                        .equals(listHourCosts.get(i).getType().getId())) {
+                    if (initDate == null || listElement.getInitDate() == null) {
+                        // this is not exactly an overlapping but a
+                        // problem with missing compulsory fields
+                        throw ValidationException.invalidValue(
+                                _("Init date cannot be empty or null"),
+                                listElement);
+                    }
+                    if (endDate == null && listElement.getEndDate() == null) {
+                        throw ValidationException.invalidValue(
+                                _("End date cannot be empty or null"),
+                                listElement);
+                    } else if ((endDate == null && listElement.getEndDate()
+                            .compareTo(initDate) >= 0)
+                            || (listElement.getEndDate() == null && listElement
+                                    .getInitDate().compareTo(endDate) <= 0)) {
+                        throw ValidationException
+                                .invalidValue(
+                                        _("Two hour costs with the same type overlap in time"),
+                                        listElement);
+                    } else if ((endDate != null && listElement.getEndDate() != null)
+                            && ((listElement.getEndDate().compareTo(initDate) >= 0 && listElement
+                                    .getEndDate().compareTo(endDate) <= 0) || (listElement
+                                    .getInitDate().compareTo(initDate) >= 0 && listElement
+                                    .getInitDate().compareTo(endDate) <= 0))) {
+                        throw ValidationException
+                                .invalidValue(
+                                        _("Two hour costs with the same type overlap in time"),
+                                        listElement);
+                    }
+                }
+            }
+        }
+    }
+
     protected CostCategory(String name) {
         this.name = name;
     }
@@ -173,42 +226,12 @@ public class CostCategory extends IntegrationEntity {
 
     @AssertFalse(message="Two hour costs with the same type overlap in time")
     public boolean checkHourCostsOverlap() {
-        List<HourCost> listHourCosts = new ArrayList<HourCost>();
-        listHourCosts.addAll(getHourCosts());
-        for(int i=0; i<listHourCosts.size(); i++) {
-            LocalDate initDate = listHourCosts.get(i).getInitDate();
-            LocalDate endDate = listHourCosts.get(i).getEndDate();
-            for(int j=i+1; j<listHourCosts.size(); j++) {
-                HourCost listElement = listHourCosts.get(j);
-                if (listElement.getType() == null || listHourCosts.get(i).getType() == null) {
-                    //this is not exactly an overlapping but a
-                    //problem with missing compulsory fields
-                    return true;
-                }
-                if(listElement.getType().getId().equals(listHourCosts.get(i).getType().getId())) {
-                    if (initDate == null || listElement.getInitDate() == null) {
-                        //this is not exactly an overlapping but a
-                        //problem with missing compulsory fields
-                        return true;
-                    }
-                    if (endDate == null && listElement.getEndDate() == null) {
-                        return true;
-                    }
-                    else if((endDate == null && listElement.getEndDate().compareTo(initDate)>=0) ||
-                            (listElement.getEndDate() == null && listElement.getInitDate().compareTo(endDate)<=0)) {
-                        return true;
-                    }
-                    else if((endDate != null && listElement.getEndDate() != null) &&
-                            ((listElement.getEndDate().compareTo(initDate)>=0 &&
-                            listElement.getEndDate().compareTo(endDate)<=0) ||
-                            (listElement.getInitDate().compareTo(initDate)>=0 &&
-                                    listElement.getInitDate().compareTo(endDate)<=0))) {
-                        return true;
-                    }
-                }
-            }
+        try {
+            validateHourCostsOverlap(getHourCosts());
+            return false;
+        } catch (ValidationException e) {
+            return true;
         }
-        return false;
     }
 
     @Override
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryCRUDController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryCRUDController.java
index bc9040cd9..cbf0a051a 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryCRUDController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryCRUDController.java
@@ -31,6 +31,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.apache.commons.logging.LogFactory;
+import org.hibernate.validator.InvalidValue;
 import org.joda.time.LocalDate;
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
 import org.navalplanner.business.common.exceptions.ValidationException;
@@ -45,7 +46,9 @@ import org.navalplanner.web.common.OnlyOneVisible;
 import org.navalplanner.web.common.Util;
 import org.navalplanner.web.common.components.Autocomplete;
 import org.navalplanner.web.workreports.WorkReportCRUDController;
+import org.zkoss.ganttz.util.ComponentsFinder;
 import org.zkoss.zk.ui.Component;
+import org.zkoss.zk.ui.WrongValueException;
 import org.zkoss.zk.ui.event.CheckEvent;
 import org.zkoss.zk.ui.event.Event;
 import org.zkoss.zk.ui.event.EventListener;
@@ -68,6 +71,7 @@ import org.zkoss.zul.api.Window;
  * Controller for CRUD actions over a {@link CostCategory}
  *
  * @author Jacobo Aragunde Perez <jaragunde@igalia.com>
+ * @author Diego Pino García <dpino@igalia.com>
  */
 @SuppressWarnings("serial")
 public class CostCategoryCRUDController extends GenericForwardComposer
@@ -164,20 +168,36 @@ public class CostCategoryCRUDController extends GenericForwardComposer
     }
 
     public boolean save() {
-        if(!ConstraintChecker.isValid(createWindow)) {
+        if (!ConstraintChecker.isValid(createWindow)) {
             return false;
         }
+
+        try {
+            costCategoryModel.validateHourCostsOverlap();
+        } catch (ValidationException e) {
+            showHoursCostsOverlapValidationException(e);
+        }
+
         try {
             costCategoryModel.confirmSave();
-            messagesForUser.showMessage(Level.INFO,
-                    _("Cost category saved"));
+            messagesForUser.showMessage(Level.INFO, _("Cost category saved"));
             return true;
         } catch (ValidationException e) {
+            e.getInvalidValue().getValue();
             messagesForUser.showInvalidValues(e);
         }
         return false;
     }
 
+    private void showHoursCostsOverlapValidationException(ValidationException e) {
+        InvalidValue invalid = e.getInvalidValue();
+        Row comp = ComponentsFinder.findRowByValue(listHourCosts,
+                invalid.getValue());
+        if (comp != null) {
+            throw new WrongValueException(comp, invalid.getMessage());
+        }
+    }
+
     public CostCategory getCostCategory() {
         return costCategoryModel.getCostCategory();
     }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryModel.java
index 657677a32..57150a9a7 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/CostCategoryModel.java
@@ -47,6 +47,7 @@ import org.springframework.transaction.annotation.Transactional;
  * Model for UI operations related to {@link CostCategory}
  *
  * @author Jacobo Aragunde Perez <jaragunde@igalia.com>
+ * @author Diego Pino García <dpino@igalia.com>
  */
 @Service
 @Scope(BeanDefinition.SCOPE_PROTOTYPE)
@@ -181,4 +182,9 @@ public class CostCategoryModel extends IntegrationEntityModel implements
     public IntegrationEntity getCurrentEntity() {
         return this.costCategory;
     }
-}
+
+    @Override
+    public void validateHourCostsOverlap() throws ValidationException {
+        CostCategory.validateHourCostsOverlap(getCostCategory().getHourCosts());
+    }
+}
\ No newline at end of file
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/ICostCategoryModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/ICostCategoryModel.java
index d35b60db5..cacef385d 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/ICostCategoryModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/costcategories/ICostCategoryModel.java
@@ -34,6 +34,7 @@ import org.navalplanner.web.common.IIntegrationEntityModel;
  * Model for UI operations related to {@link CostCategory}
  *
  * @author Jacobo Aragunde Perez <jaragunde@igalia.com>
+ * @author Diego Pino García <dpino@igalia.com>
  */
 public interface ICostCategoryModel extends IIntegrationEntityModel {
 
@@ -62,4 +63,7 @@ public interface ICostCategoryModel extends IIntegrationEntityModel {
         throws InstanceNotFoundException;
 
     boolean canRemoveCostCategory(CostCategory category);
-}
+
+    void validateHourCostsOverlap() throws ValidationException;
+
+}
\ No newline at end of file