eurostat provides direct and free of charge online access to all its statistical databases and associated electronic publications.
World Bank Data - free and open access to data about development in countries around the globe. Users can create queries, generate charts, tables and maps and download datasets. Help tutorial is available here. There is also a Microdata Library for data collected through sample surveys of households, business establishments or other facilities.
International Monetary Fund covers a range of time series data on IMF lending, exchange rates and other economic and financial indicators. See the open access eLibrary data portal and its video tutorial.
International Labour Organization (ILO) provides access to cross-country statistics on the labour market.
Population Reference Bureau informs people around the world about population, health, and the environment.
United Nations Population Information Network - a guide to population information on UN system web sites
UNdata is a web-based data service for the global user community. It brings international statistical databases within easy reach of users through a single-entry point. Users can search and download a variety of statistical resources compiled by the United Nations (UN) statistical system and other international agencies.
United Nations Statistics Division covers different statistics databases including demographic & social, environmental & energy, gender, and so on.
The primary source for cross-nationality comparable statistics on education, science and technology, culture, and communication for more than 200 countries and territories.