Emigration from the territory of Poland was a mass phenomenon at the end of the 19th century. Its characteristic feature was that it was gainful emigration, and the predominant destination was the United States. The second most popular destination was West European countries (mainly Germany). Emigration to Russia took place on a smaller scale. In the interwar period, the rate of emigration decreased markedly. The directions also changed: the US became less popular, and emigration to France and Belgium gained in importance. Seasonal emigration (Germany, Latvia) was important from the economic and social points of view. This paper aims at analyzing the demographic dimension of both waves of emigration, and to estimate the scale and structure of emigration at regional level in 1870–1914 and 1918–1938 in order to determine net “loss” in population. The method was the analysis of census statistics from 1890–1931 at the regional level (for the late 1930s, estimates) and the analysis of emigration statistics.