Cambodia's first population census in decades, carried out in 1998, put the population of the country at 11,426,223. Phnom Penh is the largest city with a population of about one million. The most populated province is also the largest - Kompong Cham, where 14.1% of Cambodians live. The most sparsely populated is Mondulkiri, where 0.3% of the population lives, though it is one of the country's larger provinces. Krong Kep and Krong Paillin have the smallest populations of about 25,000 each, although the latter is bound to grow rapidly with an influx of former Khmer Rouge fighters and their dependents.

Ethnic Khmers : around 96% of the people who live in Cambodia are ethnic Khmers, making the country the most homogeneous in South-East Asia. In really, there are probably much higher numbers of Vietnamese and Chinese than such statistics account for.

Ethnic Vietnamese : The Vietnamese are probably the largest non-khmers ethnic group in Cambodia. There are as high as one million.

Ethnic Chinese : there are more half a million of ethnic Chinese.

Cham Muslim : there are around half million.

Ethno-linguistic Minorities : Cambodia's diverse chunchiet who live in the country's mountainous regions, probably number from 60,000 to 70,000. Collectively, they are known as Khmer loeu ("upper Khmer").