diff --git a/bin/osv/expression.py b/bin/osv/expression.py
index 3281fd29f7c..cbb6a0f985b 100644
--- a/bin/osv/expression.py
+++ b/bin/osv/expression.py
@@ -143,12 +143,18 @@ class expression(object):
             if len(fargs) > 1:
                 if field._type == 'many2one':
                     right = field_obj.search(cr, uid, [(fargs[1], operator, right)], context=context)
-                    self.__exp[i] = (fargs[0], 'in', right)
+                    if right == []:
+                        self.__exp[i] = ( 'id', '=', 0 )
+                    else:
+                        self.__exp[i] = (fargs[0], 'in', right)
                 # Making search easier when there is a left operand as field.o2m or field.m2m
                 if field._type in ['many2many','one2many']:
                     right = field_obj.search(cr, uid, [(fargs[1], operator, right)], context=context)
                     right1 = table.search(cr, uid, [(fargs[0],'in', right)], context=context)
-                    self.__exp[i] = ('id', 'in', right1)
+                    if right1 == []:
+                        self.__exp[i] = ( 'id', '=', 0 )
+                    else:
+                        self.__exp[i] = ('id', 'in', right1)
                 
                 if not isinstance(field,fields.property):
                     continue
@@ -313,6 +319,13 @@ class expression(object):
                                 if not isinstance(ele, basestring): 
                                     m2o_str = False
                                     break
+                    elif right == []:
+                        m2o_str = False
+                        if operator in ('not in', '!=', '<>'):
+                            # (many2one not in []) should return all records
+                            self.__exp[i] = self.__DUMMY_LEAF
+                        else:
+                            self.__exp[i] = ('id','=',0)
                     else:
                         new_op = '='
                         if operator in  ['not like','not ilike','not in','<>','!=']: