Nigeria has a population of 140,003,542, confirming its status as the most populous country in Africa according to the results of a census conducted by the National Population Commission (NPC) in March 2006. Men outnumber women by 71,709,859 to 68,293,683, representing a ratio of 105 to 100. The population growth rate stands at 3.2 per cent, against 2.8 per cent when the last census was conducted in 1991. Then the headcount put the population of Nigeria at 88.9 million.

Kano in the mainly Muslim north of the country emerged as being the most populous state, with an official population of around 9.4 million. It is closely followed by Lagos State (9 million) in the mainly Christian and animist south.

The census forms included questions about educational background, income, type of housing, toilet facilities, water supply and access to the media, but not about the controversial issues of religion and ethnicity. The operation was conducted over a five-day period at a cost of N36 billion.