diff --git a/openerp/addons/base/ir/ir_attachment.py b/openerp/addons/base/ir/ir_attachment.py
index 97edffd6ada..ad257b418c3 100644
--- a/openerp/addons/base/ir/ir_attachment.py
+++ b/openerp/addons/base/ir/ir_attachment.py
@@ -133,7 +133,7 @@ class ir_attachment(osv.osv):
             else:
                 result[attach.id] = attach.db_datas
                 if bin_size:
-                    result[attach.id] = int(result[attach.id])
+                    result[attach.id] = int(result[attach.id] or 0)
 
         return result