There are 38,610,097 people in Kenya, according to the official 2009 population census figures released on Tuesday.
Out of these, men and women seem to have struck a balance, nearly, with 19,192,458 being male and 19,417,639 female.
Releasing the results on Tuesday in Nairobi, Planning minister Wycliffe Oparanya, however, said a repeat census has been ordered in eight districts after inconsistencies were noted in the population data for areas in northern Kenya.
The districts affected are Lagdera, Wajir East, Mandera Central, Mandera East, Mandera West, Turkana Central, Turkana North, and Turkana South.
Mr Oparanya said the inconsistencies in these regions were arising from the rate of population increase being higher than what birth and death rates would support, and age and sex profiles deviating from normal.
Releasing the census data exactly a year after the count, Mr Oparanya said the results are phased in different categories including: by administrative units, political units, by age and gender, and by cultural and socio-economic clusters.
Notably, the results include figures by ethnic and religious affiliation.
According to the census, the top ethnic communities by numbers are Kikuyu at 6.62 million, Luhya 5.33 million, the Kalenjin at 4.96 million, and Luo 4.04 million,
Others are Kamba (3.89 million), Kenyan Somali (2.38 million), Kisii (2.21 million), Mijikenda (1.96 million), Meru (1.65 million), Turkana (0.99 million), Maasai (0.84 million), Teso (0.33 million) and Embu (0.32 million) among others.
The census results indicate that Protestants churches enjoy the biggest following in the country, with 18.3 million followers.
They are followed by the Catholic Church with 9,010,684 followers while other Christian churches account for 4,559,584 followers.
The Muslim population in the country stands at 4,304,798 while that of Hindus is 53,393.
The last census in 1999 showed the number of Kenyans at 28.7 million, representing a growth of 10 million people within a decade.
On Monday, Mr Oparanya said giving the population of ethnic and religious groups should be taken positively because it will assist in general national development plans.
He said that, for the first time, population growth would be captured at intervals of five years, a development he said will make it easy to capture the data of both the young and the elderly.
The population data, which is being released after Kenya proclaimed a new Constitution, also shows the population by 47 counties created in the new law.
Nairobi leads the list of most populous county with 3.1 million people, followed by Kakamega, Bungoma, Kiambu, Nakuru and Meru. Other most populated counties with more than a million people are Kisii, Kilifi, Machakos and Mandera.
By provinces, Rift Valley leads with 10.1 million followed by Eastern (5.6 million) Nyanza (5.4 million) Central (4.4 million) and Western (4.3 million)
Coast Province has 3.3 million people, Nairobi (3.1 million) with North Eastern having the least number of people at 2.3 million.
The census report also shows most and least populated districts, with areas in Nairobi topping the list.
Siaya, Molo, Kirinyaga, Mombasa, Igembe, Kisumu East and Nakuru are in the list of ten most populated districts in Kenya, while Laikipia North, Garbatulla, Marsabit, Samburu, Taveta are indicated as some of the areas having the least number of people.
Kenya's population has grown incrementally from the 2.5 million at the beginning of the last century to the current figure. In 1962, just before the country gained independence from the British, Kenya had 8.62 million people, a figure which rose to 10.9 million at the 1969 census, 15.3 million in 1979 and up to 21.4 million in 1989.
A total of Sh8.4 billion was spent in conducting the last census, with more than of that money being payments to the census staff. The release of the results has been postponed twice, because of what the Government termed as "“complexities in data analysis”.
Mr Oparanya cited challenges to the census exercise such as cash-flow problems, insecurity concerns, complex logistics for the counting of pastoralist communities and creation of new districts which raised the census budget. He also noted "competing national interests such as famine, drought, resettlement of IDPs", and post-election violence which disrupted mapping activities.