Cognomen Mačaj (Mačaj 
, Мачай 
) , all around the world, is a rare last name. The family name Mačaj is habitual in Eastern Europe, particularly Slovakia, where it is a rare surname, Ukraine, and Russia, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Mačaj | Slovakia |
| Мачай | Ukraine, Russia |