Egypt's population has grown by more than 20% in the past decade and has doubled in the last 30 years, the government statistics agency says.
Egypt's capital now has more than 18 million inhabitants
The population, including those living abroad, reached 76.5m in 2006 and one Egyptian baby was born every 23 seconds during the year, the census says.
Cairo's population rose to more than 18m, although figures suggest large-scale rural migration has ended.
The 1882 census, the first in modern times, showed a population of 6.7m.
Although nearly one-third of the population was under 15 last year, the average family size is falling from 4.65 people in 1996 to 4.18 in 2006.
"This decrease shows that parents are reducing their new births to give their other children a better standard of living," Gen Abu Bakr al-Gendi, the head of Egypt's statistics centre, told AFP news agency.
The expatriate population stands at about four million, the census said.
The census also revealed that the percentage of illiterate Egyptians had fallen to 29% from 39% over the past 10 years.
An average of 500,000 marriages took place annually and there were 60,000 divorces.
While the vast majority of people have access to clean water and electricity (95% and 99%), only half had access to a proper sewerage system.
The government does not count how many people in the mainly Muslim state are Coptic Christians. The minority claims to face official discrimination, although the government denies this.