Surname Деморчук (Деморчук 
) , all around the world, is a very rare cognomen. The surname Деморчук is characteristic of Russia, where it is a very rare surname, Kazakhstan, and Ukraine, where it is an extremely rare surname. Very seldom, Деморчук is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Деморчук | Kazakhstan, Ukraine, Russia |