diff --git a/addons/mrp/mrp.py b/addons/mrp/mrp.py
index cf203a60c7f..a570842a36e 100644
--- a/addons/mrp/mrp.py
+++ b/addons/mrp/mrp.py
@@ -274,6 +274,17 @@ class mrp_bom(osv.osv):
             return {'value': {'name': prod.name, 'product_uom': prod.uom_id.id}}
         return {}
 
+    def onchange_uom(self, cr, uid, ids, product_id, product_uom, context=None):
+        res = {'value':{}}
+        if not product_uom or not product_id:
+            return res
+        product = self.pool.get('product.product').browse(cr, uid, product_id, context=context)
+        uom = self.pool.get('product.uom').browse(cr, uid, product_uom, context=context)
+        if uom.category_id.id != product.uom_id.category_id.id:
+            res['warning'] = {'title': _('Warning'), 'message': _('Selected Unit of Measure does not belong to the same category as the product Unit of Measure.')}
+            res['value'].update({'product_uom': product.uom_id.id})
+        return res
+
     def _bom_find(self, cr, uid, product_id, product_uom, properties=None):
         """ Finds BoM for particular product and product uom.
         @param product_id: Selected product.
diff --git a/addons/mrp/mrp_view.xml b/addons/mrp/mrp_view.xml
index abf0f823e5c..dca41050430 100644
--- a/addons/mrp/mrp_view.xml
+++ b/addons/mrp/mrp_view.xml
@@ -351,7 +351,7 @@
                             <label for="product_qty" string="Quantity"/>
                             <div>
                                 <field name="product_qty" class="oe_inline"/>
-                                <field name="product_uom" class="oe_inline" groups="product.group_uom"/>
+                                <field name="product_uom" class="oe_inline" on_change="onchange_uom(product_id, product_uom)" groups="product.group_uom"/>
                             </div>
                             <label for="product_uos_qty" groups="product.group_uos"/>
                             <div groups="product.group_uos" >
@@ -382,7 +382,7 @@
                                 <tree string="Components" editable="bottom">
                                     <field name="product_id" on_change="onchange_product_id(product_id, name)"/>
                                     <field name="product_qty"/>
-                                    <field name="product_uom" groups="product.group_uom"/>
+                                    <field name="product_uom" on_change="onchange_uom(product_id, product_uom)" groups="product.group_uom"/>
                                     <field name="name" invisible="1"/>
                                     <field name="date_start"/>
                                     <field name="date_stop"/>