diff --git a/addons/crm/base_partner_merge.py b/addons/crm/base_partner_merge.py
index 84038986396..560de0ecc51 100644
--- a/addons/crm/base_partner_merge.py
+++ b/addons/crm/base_partner_merge.py
@@ -300,6 +300,12 @@ class MergePartnerAutomatic(osv.TransientModel):
         if len(partner_ids) > 3:
             raise osv.except_osv(_('Error'), _("For safety reasons, you cannot merge more than 3 contacts together. You can re-open the wizard several times if needed."))
 
+        child_ids = set()
+        for partner_id in partner_ids:
+            child_ids = child_ids.union(set(proxy.search(cr, uid, [('id', 'child_of', [partner_id])])) - set([partner_id]))
+        if set(partner_ids).intersection(child_ids):
+            raise osv.except_osv(_('Error'), _("You cannot merge a contact with one of his parent."))
+
         if openerp.SUPERUSER_ID != uid and len(set(partner.email for partner in proxy.browse(cr, uid, partner_ids, context=context))) > 1:
             raise osv.except_osv(_('Error'), _("All contacts must have the same email. Only the Administrator can merge contacts with different emails."))
 
diff --git a/addons/crm/i18n/crm.pot b/addons/crm/i18n/crm.pot
index 310f7e5f9ef..40e330490f0 100644
--- a/addons/crm/i18n/crm.pot
+++ b/addons/crm/i18n/crm.pot
@@ -3056,6 +3056,12 @@ msgid "You are already at the top level of your sales-team category.\n"
 "Therefore you cannot escalate furthermore."
 msgstr ""
 
+#. module: crm
+#: code:addons/crm/base_partner_merge.py:310
+#, python-format
+msgid "You cannot merge a contact with one of his parent."
+msgstr ""
+
 #. module: crm
 #: code:addons/crm/base_partner_merge.py:446
 #, python-format