diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/materials/UnitTypeController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/materials/UnitTypeController.java
index 77271578c..9f52f173b 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/materials/UnitTypeController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/materials/UnitTypeController.java
@@ -39,6 +39,7 @@ import org.zkoss.zk.ui.event.CheckEvent;
 import org.zkoss.zk.ui.event.Event;
 import org.zkoss.zk.ui.event.EventListener;
 import org.zkoss.zk.ui.event.Events;
+import org.zkoss.zul.Button;
 import org.zkoss.zul.Constraint;
 import org.zkoss.zul.Hbox;
 import org.zkoss.zul.Label;
@@ -96,13 +97,17 @@ public class UnitTypeController extends BaseCRUDController<UnitType> {
                     }
                 }));
 
-                hbox.appendChild(Util.createRemoveButton(new EventListener() {
+                Button removeButton = Util
+                        .createRemoveButton(new EventListener() {
 
                     @Override
                     public void onEvent(Event event) {
                         confirmDelete(unitType);
                     }
-                }));
+                });
+                removeButton.setDisabled(unitTypeModel
+                        .isUnitTypeUsedInAnyMaterial(unitType));
+                hbox.appendChild(removeButton);
 
                 row.appendChild(hbox);
             }