1) Russian surname 2) Ukrainian surname 
Kovalchuk (Russian, Ukrainian: Ковальчу́к), Kavalchuk (Belarusian: Кавальчу́к), Kowalczuk (Polish), also transliterated as a German adaptation Kowalchuk (in the North American diaspora), is a common East Slavic surname (one of the most popular in Ukraine). The Kovalchuk name extends back to before 1500 AD in the Kievan Rus.{cit...