diff --git a/openerp/addons/base/ir/ir_model.py b/openerp/addons/base/ir/ir_model.py
index 824caeb23a7..2f05bfc75bb 100644
--- a/openerp/addons/base/ir/ir_model.py
+++ b/openerp/addons/base/ir/ir_model.py
@@ -502,7 +502,8 @@ class ir_model_access(osv.osv):
             model_name = model
 
         # TransientModel records have no access rights, only an implicit access rule
-        if self.pool.get(model_name).is_transient():
+        model_obj = self.pool.get(model_name)
+        if model_obj and model_obj.is_transient():
             return True
 
         # We check if a specific rule exists