The paper aims to identify the nature of unemployment and factors determining its level in Poland from 2006 to 2009. The research was conducted on the basis of selected unpublished data for both the entire population (Poland as a whole) covered by labor force surveys and for specific population groups singled out on the basis of characteristics such as gender, age, education, and place of residence. The so-called labor market flows approach – Inflow-Outflow Analysis (IOA) – was used to assess the rates of inflow to and outflow from unemployment, as well as the average duration of unemployment. Using the CEPR method developed by the London-based Centre for Economic Policy Research (CEPR), based on the analysis of flows between different states of economic activity of the population, the natural rate of unemployment was calculated. The estimated values of the natural rate of unemployment were compared with the real unemployment rate and the Non-Accelerating Inflation Rate of Unemployment (NAIRU) in each quarter of the analyzed period. Then, the relationship between the real unemployment rate and the natural rate of unemployment in each population group was examined to determine the size of the structural and cyclical components of unemployment. When analyzing the relationship between the CEPR natural rate of unemployment and the real unemployment rate, the authors distinguished three sub-periods in the studied period. In the first sub-period, the real unemployment rate decreased, while the natural rate of unemployment increased. In the second sub-period, the natural rate of unemployment mirrored the real unemployment rate. In the third sub-period, the gap between the real unemployment rate and the natural rate of unemployment widened as a result of a halted decline in the real unemployment rate. Some population groups and problem areas were isolated, where despite the structural nature of unemployment, it is reasonable to take action aimed at stimulating economic activity and job creation. In terms of the urban-rural breakdown, the smallest towns and rural areas are the key problem areas, and in terms of labor force characteristics, the youngest people entering the labor market as well as poorly educated individuals and those nearing retirement are the main problem groups. Gender is an important determinant of both employment and the risk of unemployment, the authors say, but the differences between men and women in this area were smaller than expected.