In this paper the authors analyze the evolution and the determinants of in-work poverty in Poland, according to three poverty lines: relative, absolute, and the 1998-adjusted poverty line. The authors find that behind moderately high in-work poverty incidence in Poland there is very high in-work poverty in agriculture and modest in-work poverty in all other sectors. Workers are much less likely to be poor than jobless individuals, especially the unemployed. In fact, the share of adults out of employment is a much stronger predictor of households' risk of poverty than the level of wages at which they work. Moreover, the share of jobless adults or of agricultural workers has become an increasing determinant of in-work poverty over time. The risk of in-work poverty is also inversely related to the educational attainment and the stability of employment of an individual, which is especially important considering that the incidence of temporary contracts in Poland is the highest across both European Union (EU) and Organization of Economic Cooperation and Development (OECD) countries. Existing fiscal and benefit policies have not been sufficient to address in-work poverty and some of its underlying causes in the labor market: the author presents four policy recommendations aimed at tackling in-work and total poverty, and at increasing labor market participation and employment.