The Czechoslovak socialist regime declared equal treatment of people on the labour market. This position reflected Marxist-Leninist ideology. The goal of this paper is to find out how this formal equal treatment was implemented in everyday practice. The answers are based on our unique research among managers of socialist companies from the 1970s and 1980s. We found out that in practice the regime discriminated some subgroups on the labor market positively as well as negatively even though the wages were formally set in a remarkably equal way.