EN
This paper concerns the interpretation problems accompanying the contemporary surnames with the formative -yk/-czyk (on the example of the Białystok region). Its aim is to present various manners of explaining the origin of anthroponyms with this suffix. As the analysis has shown, the complexity of the problems involved in determining the etymology of the discussed surnames is manifested mainly (Dziemiańczyk, Tomczyk), appellative surnames (Gołowaczyk, Kulawczyk), surnames coined based on expressions indicating a profession or function (Atamańczyk, Tokarczyk), and ones coined based on place names (Majdańczyk, Nurczyk).