The transition of Poland to a free market economy, concurrent to a substantial increase of the private sector, promoted entrepreneurship, joint ventures, self-employment, labor reallocation, growth of financial markets and direct foreign investments. Previous studies have provided inconclusive evidence regarding earning disparities in Poland. The present study proposes a model that employs demographic, employment and organizational characteristics, revealing that earnings in the private sector are 9.8% higher than in the public sector; human capital characteristics are more influential in the private than in the public sector; the return to general training is higher for both workers with a higher education and those in the private sector; and the return to firm-specific-training is higher in the private sector. The results are discussed in light of the structure of a transitional economy and the changing labor market