As an ordinary visa can be extended indefinitely permanent residency is not available in Cambodia. If you decide to stay then you can simply continue to extend your business visa each year, or you may choose to become a Cambodian citizen, but this is not necessary.
Applications for Cambodian citizenship are processed by the Ministry of the Interior and the process can take 2 to 3 months. It is possible to become a Cambodian citizen but remain a citizen of your former country and have dual nationality, depending on the laws in your home country.
The main benefit of being a Cambodian citizen, if you intend to live there long term, is that you are able to own land in the country. However, it is not as easy to gain citizenship as you might think. Recently the cash donation required for citizenship has been significantly increased.
Citizenship can be obtained through a donation of US$310,000 to the Cambodian government for the benefit of the Cambodian people.
Alternatively, to become a citizen of Cambodia you must have lived and worked in the country for at least seven years. You will also be required to sit an exam to prove proficiency in reading, writing and speaking Khmer.
Marriage to a Cambodian is another way in which citizenship is granted, however, this can only take place after three years of cohabitation following the registration of the marriage. Any children born in Cambodia take the nationality of their father regardless of whether or not he is Cambodian.