diff --git a/addons/account/tests/test_search.py b/addons/account/tests/test_search.py
index 0e93da0c0bc..6f4a56cf8e6 100644
--- a/addons/account/tests/test_search.py
+++ b/addons/account/tests/test_search.py
@@ -12,6 +12,8 @@ class TestSearch(TransactionCase):
         cr, uid = self.cr, self.uid
         self.account_model = self.registry('account.account')
         self.account_type_model = self.registry('account.account.type')
+        self.res_partner_model = self.registry('res.partner')
+        self.account_payment_term_model = self.registry('account.payment.term')
         ac_ids = self.account_type_model.search(cr, uid, [], limit=1)
         self.atax = (int(self.account_model.create(cr, uid, dict(
             name="Tax Received",
@@ -33,6 +35,9 @@ class TestSearch(TransactionCase):
 
         self.all_ids = [self.atax[0], self.apurchase[0], self.asale[0]]
 
+        self.a_partner = self.res_partner_model.create(cr, uid, {'name':'test partner'})
+        self.a_payment_term = self.account_payment_term_model.create(cr, uid, {'name':'test payment term'})
+
     def test_name_search(self):
         cr, uid = self.cr, self.uid
         atax_ids = self.account_model.name_search(cr, uid, name="Tax", operator='ilike', args=[('id', 'in', self.all_ids)])
@@ -58,3 +63,13 @@ class TestSearch(TransactionCase):
 
         asale_ids = self.account_model.name_search(cr, uid, name='Product Sales', operator='not ilike', args=[('id', 'in', self.all_ids)])
         self.assertEqual(set([self.atax[0], self.apurchase[0]]), set([a[0] for a in asale_ids]), "name_search 'not ilike Product Sales' should have returned all but Product Sales account")
+
+    def test_property_unset_search(self):
+        cr, uid = self.cr, self.uid
+
+        partner_ids = self.res_partner_model.search(cr, uid, [('property_payment_term', '=', False), ('id', '=', self.a_partner)])
+        self.assertTrue(partner_ids, "unset property field 'propety_payment_term' should have been found")
+
+        self.res_partner_model.write(cr, uid, [self.a_partner], {'property_payment_term': self.a_payment_term})
+        partner_ids = self.res_partner_model.search(cr, uid, [('property_payment_term', '=', False), ('id', '=', self.a_partner)])
+        self.assertFalse(partner_ids, "set property field 'propety_payment_term' should not have been found")
diff --git a/openerp/addons/base/res/ir_property.py b/openerp/addons/base/res/ir_property.py
index 859f97330d4..f14c68d06d3 100644
--- a/openerp/addons/base/res/ir_property.py
+++ b/openerp/addons/base/res/ir_property.py
@@ -259,12 +259,19 @@ class ir_property(osv.osv):
     @api.model
     def search_multi(self, name, model, operator, value):
         """ Return a domain for the records that match the given condition. """
+        default_matches = False
+
         field = self.env[model]._fields[name]
         if field.type == 'many2one':
             comodel = field.comodel_name
             def makeref(value):
                 return value and '%s,%s' % (comodel, value)
-            if operator in ('=', '!=', '<=', '<', '>', '>='):
+            if operator == "=":
+                value = makeref(value)
+                # if searching properties not set, search those not in those set
+                if value is False:
+                    default_matches = True
+            elif operator in ('!=', '<=', '<', '>', '>='):
                 value = makeref(value)
             elif operator in ('in', 'not in'):
                 value = map(makeref, value)
@@ -283,7 +290,6 @@ class ir_property(osv.osv):
 
         # retrieve the records corresponding to the properties that match
         good_ids = []
-        default_matches = False
         for prop in props:
             if prop.res_id:
                 res_model, res_id = prop.res_id.split(',')