The Phnom Penh municipal court also found Hugo Leuthold guilty of illegally entering the country.
The court sentenced him to five years in jail and ordered him to pay a compensation of two million riel (around $500) to the complainant.
The man will be expelled from the country after his jail term.
Leuthold was arrested in March in a hotel in Phnom Penh where he had sex with a minor under 15.
The man had been previously arrested on Christmas day in 2010 in Sihanoukville and later sentenced to two years in prison for sexually abusing four boys aged between 11 and 13. He was, however, released after 10 months in jail.
Phnom Penh: An 81-year-old Swiss man was on Friday convicted by a court in Cambodia's capital for his involvement in child prostitution. He was sentenced to five years in jail, Xinhua reported.
First Published: Friday, September 14, 2012, 22:06