DIOC is a database compiled by the OECD on the immigrant populations in the countries belonging to the organization. The database provides micro-data from the population censuses of these countries on, in particular, the naturalness and nationality of migrants and their demographic characteristics, level of education, insertion in the labor market and length of stay. The bases designated DIOC-E include less detailed information on censuses conducted in OECD countries and non-OECD countries (around 100).

The four bases now available, of 2000/01 and 2010/11, in the restricted and expanded versions, that can be accessed here.