diff --git a/bitmask/bitmask.go b/bitmask/bitmask.go
index 5d3ac7f..237fae8 100644
--- a/bitmask/bitmask.go
+++ b/bitmask/bitmask.go
@@ -56,7 +56,7 @@ func (m *MaskBit) AddFlag(flag MaskBit) {
 // ClearFlag removes MaskBit flag from m.
 func (m *MaskBit) ClearFlag(flag MaskBit) {
 
-	*m &= flag
+	*m &^= flag
 
 	return
 }