In this paper I present a new database of bilateral migrant stocks, and I provide new evidence on the determinants of international migration. The new Census-based data are obtained from the National Statistical Offices of 24 OECD countries, and they cover the total stock of immigrants in each destination country for 1960-2000, including 188 countries of origin. Empirically, I find strong evidence of heterogeneous effects of income gains on migration prospects depending on distance. For example, a 1,000 $ increase in U.S. income per capita increases the stock of Mexican immigrants in the country by a percentage three times larger than the percentage increase in the stock of Chinese.