diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementController.java
index c2d413808..c73dc52c3 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementController.java
@@ -57,11 +57,26 @@ public class AssignedLabelsToOrderElementController extends
 
         final String labelName = txtLabelName.getValue();
         final LabelType labelType = (LabelType) comboitem.getValue();
-        if (!assignedLabelsToOrderElementModel.existsLabelByNameAndType(
-                labelName, labelType)) {
-            final Label label = createLabel(labelName, labelType);
-            assignLabel(label);
+
+        // Label does not exist, create
+        Label label = assignedLabelsToOrderElementModel
+                .findLabelByNameAndType(labelName, labelType);
+        if (label == null) {
+            label = createLabel(labelName, labelType);
+        } else {
+            // Label is already assigned?
+            if (isAssigned(label)) {
+                throw new WrongValueException(txtLabelName,
+                        _("already assigned"));
+            }
         }
+
+        // Assign label
+        assignLabel(label);
+    }
+
+    private boolean isAssigned(Label label) {
+        return assignedLabelsToOrderElementModel.isAssigned(label);
     }
 
     private void assignLabel(Label label) {
@@ -74,11 +89,6 @@ public class AssignedLabelsToOrderElementController extends
                 labelType);
     }
 
-    private void addLabel(String labelName, LabelType labelType) {
-        assignedLabelsToOrderElementModel.addLabel(labelName, labelType);
-        Util.reloadBindings(directLabels);
-    }
-
     public List<Label> getLabels() {
         return assignedLabelsToOrderElementModel.getLabels();
     }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementModel.java
index 31ee55c02..9fb76cffd 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/AssignedLabelsToOrderElementModel.java
@@ -36,10 +36,19 @@ public class AssignedLabelsToOrderElementModel implements
 
     OrderElement orderElement;
 
+    @Override
+    public OrderElement getOrderElement() {
+        return orderElement;
+    }
+
+    @Override
+    public void setOrderElement(OrderElement orderElement) {
+        this.orderElement = orderElement;
+    }
+
     @Override
     @Transactional(readOnly = true)
     public void init(OrderElement orderElement) {
-        // orderDAO.save(orderElement);
         this.orderElement = orderElement;
         reattachOrderElement(this.orderElement);
     }
@@ -55,11 +64,15 @@ public class AssignedLabelsToOrderElementModel implements
 
     private void reattachLabels(Set<Label> labels) {
         for (Label label : labels) {
-            label.getName();
-            label.getType().getName();
+            reattachLabel(label);
         }
     }
 
+    public void reattachLabel(Label label) {
+        label.getName();
+        label.getType().getName();
+    }
+
     @Transactional(readOnly = true)
     public List<Label> getLabels() {
         List<Label> result = new ArrayList<Label>();
@@ -69,16 +82,26 @@ public class AssignedLabelsToOrderElementModel implements
         return result;
     }
 
+    @Override
     @Transactional(readOnly = true)
-    public boolean existsLabelByNameAndType(String labelName,
-            LabelType labelType) {
-        return (labelDAO.findByNameAndType(labelName, labelType) != null);
+    public List<Label> getInheritedLabels() {
+        List<Label> result = new ArrayList<Label>();
+
+        if (orderElement != null) {
+            OrderLineGroup parent = orderElement.getParent();
+            while (parent != null) {
+                reattachOrderElement(parent);
+                result.addAll(parent.getLabels());
+                parent = parent.getParent();
+            }
+        }
+        return result;
     }
 
-    public void addLabel(String labelName, LabelType labelType) {
+    public Label createLabel(String labelName, LabelType labelType) {
         Label label = Label.create(labelName);
         label.setType(labelType);
-        orderElement.addLabel(label);
+        return label;
     }
 
     public void assignLabel(Label label) {
@@ -92,43 +115,23 @@ public class AssignedLabelsToOrderElementModel implements
 
     @Override
     @Transactional(readOnly = true)
-    public List<Label> getInheritedLabels() {
-        System.out.println("### getInheritedLabels");
-
-        List<Label> result = new ArrayList<Label>();
-
-        if (orderElement != null) {
-            OrderLineGroup parent = orderElement.getParent();
-            while (parent != null) {
-                reattachOrderElement(parent);
-                // System.out.println("### labels: " + parent.getLabels());
-                result.addAll(parent.getLabels());
-                parent = parent.getParent();
-            }
+    public Label findLabelByNameAndType(String labelName, LabelType labelType) {
+        final Label label = labelDAO.findByNameAndType(labelName, labelType);
+        if (label != null) {
+            reattachLabel(label);
         }
-        return result;
-    }
-
-    @Override
-    public OrderElement getOrderElement() {
-        return orderElement;
-    }
-
-    @Override
-    public void setOrderElement(OrderElement orderElement) {
-        this.orderElement = orderElement;
-    }
-
-    /**
-     *
-     * @param labelName
-     * @param labelType
-     * @return
-     */
-    public Label createLabel(String labelName, LabelType labelType) {
-        Label label = Label.create(labelName);
-        label.setType(labelType);
         return label;
     }
 
+    @Override
+    public boolean isAssigned(Label label) {
+        final Set<Label> labels = orderElement.getLabels();
+
+        for (Label element : labels) {
+            if (element.getId().equals(label.getId())) {
+                return true;
+            }
+        }
+        return false;
+    }
 }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/IAssignedLabelsToOrderElementModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/IAssignedLabelsToOrderElementModel.java
index 484c49dfc..ad72aa060 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/IAssignedLabelsToOrderElementModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/IAssignedLabelsToOrderElementModel.java
@@ -12,32 +12,43 @@ import org.navalplanner.business.orders.entities.OrderElement;
 public interface IAssignedLabelsToOrderElementModel {
 
     /**
+     * Assigns {@link Label} to {@link OrderElement}
+     *
+     * @param label
+     */
+    void assignLabel(Label label);
+
+    /**
+     * Creates new {@link Label}
      *
      * @param labelName
      * @param labelType
      * @return
      */
-    boolean existsLabelByNameAndType(String labelName, LabelType labelType);
+    Label createLabel(String labelName, LabelType labelType);
 
     /**
+     * Delete {@link Label}
+     *
+     * @param label
+     */
+    void deleteLabel(Label label);
+
+    /**
+     * Returns {@link Label} by name and type
      *
      * @param labelName
      * @param labelType
+     * @return
      */
-    void addLabel(String labelName, LabelType labelType);
+    Label findLabelByNameAndType(String labelName, LabelType labelType);
 
     /**
+     * Returns all {@link Label} from {@link OrderElement} ancestors
      *
      * @return
      */
-    OrderElement getOrderElement();
-
-    /**
-     * Set {@link OrderElement}
-     *
-     * @param orderElement
-     */
-    void setOrderElement(OrderElement orderElement);
+    List<Label> getInheritedLabels();
 
     /**
      * Returns {@link OrderElement}
@@ -46,32 +57,27 @@ public interface IAssignedLabelsToOrderElementModel {
      */
     public List<Label> getLabels();
 
-    /**
-     *
-     * @param label
-     */
-    void deleteLabel(Label label);
-
     /**
      *
      * @return
      */
-    List<Label> getInheritedLabels();
+    OrderElement getOrderElement();
 
     void init(OrderElement orderElement);
 
     /**
-     *
-     * @param labelName
-     * @param labelType
-     * @return
-     */
-    Label createLabel(String labelName, LabelType labelType);
-
-    /**
+     * Check whether {@link Label} has been already assigned to
+     * {@link OrderElement} or not
      *
      * @param label
      */
-    void assignLabel(Label label);
+    boolean isAssigned(Label label);
+
+    /**
+     * Set {@link OrderElement}
+     *
+     * @param orderElement
+     */
+    void setOrderElement(OrderElement orderElement);
 
 }