EN
The aim of the paper is to identify determinants of the eficiency of service companies from two Central and Eastern European (CEE) countries4-Poland and Belarus. These transition economies represent diefrent economic and systemic conditions. That is why it is worth analyzing whether external conditions determine internal eficiency factors in service companies. In order to achieve that aim quantitative research was conducted among 305 Polish and Belarusian service enterprises. The research results presented significant diefrences in responses between the two countries. For Polish enterprises the main determinants of eficiency were above all connected with competent and skilled staff Belarussian companies regarded as eficiency factors which determine the demand level by means of access toward foreign markets and possibilities of internationalization. It proves that CEECs are not homogeneous and they represent diefrent levels of economic development as well as the diefrent conditions of running a business.