diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/materials/entities/MaterialAssignmentTemplate.java b/navalplanner-business/src/main/java/org/navalplanner/business/materials/entities/MaterialAssignmentTemplate.java
index ba46549c5..a94e91046 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/materials/entities/MaterialAssignmentTemplate.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/materials/entities/MaterialAssignmentTemplate.java
@@ -28,7 +28,8 @@ import org.navalplanner.business.templates.entities.OrderElementTemplate;
  * @author Óscar González Fernández <ogonzalez@igalia.com>
  *
  */
-public class MaterialAssignmentTemplate extends BaseEntity {
+public class MaterialAssignmentTemplate extends BaseEntity implements
+        Comparable<MaterialAssignmentTemplate> {
 
     public static MaterialAssignmentTemplate copyFrom(
             MaterialAssignmentTemplate assignment) {
@@ -111,4 +112,9 @@ public class MaterialAssignmentTemplate extends BaseEntity {
         return getMaterialInfo().getTotalPrice();
     }
 
+    @Override
+    public int compareTo(MaterialAssignmentTemplate o) {
+        return getMaterial().compareTo(o.getMaterial());
+    }
+
 }