diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 92a22a29f9a..6f794469529 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -517,7 +517,8 @@ def get_pg_type(f, type_override=None):
     elif issubclass(field_type, (fields.char, fields.reference)):
         return ('varchar', pg_varchar(f.size))
     elif issubclass(field_type, fields.selection):
-        if isinstance(f.selection, list) and isinstance(f.selection[0][0], int):
+        if (isinstance(f.selection, list) and isinstance(f.selection[0][0], int))\
+                or getattr(f, 'size', None) == -1:
             return ('int4', 'INTEGER')
         return ('varchar', pg_varchar(getattr(f, 'size', None)))
     elif issubclass(field_type, fields.function):