Lindsey Adams, 22, and her 20-year-old sister Leslie, from Prescott, Arizona, were discovered taking 'nude pictures' inside the Preah Khan temple at the world heritage site on Friday.
Local police said the women 'lowered their pants to their knees and took pictures of their buttocks.'
The pair have been fined 1 million riel ($250) each, given six-month suspended jail sentences and are currently being deported by bus to Thailand, reports claim.
They have been banned from returning to Cambodia for four years.
A world heritage site, Angkor contains the remains of the different capitals of the Khmer Empire, dating from the 9th to the 15th centuries, and is Cambodia's most popular tourist destination.
Chau Sun Kerya, a spokeswoman for the Apsara Authority, said the women's actions were offensive because Angkor is considered sacred ground.
According to Cambodia Expats Online the pair were charged with indecent trafficking pornography and exposing sexual organs.
'Perhaps they did not know Angkor is a holy site. But their inappropriate activities affect the sanctity of the place,' she told AFP.
'The two tourists admitted that they really made a mistake by taking nude photos.'
It is the second time in the last fortnight that tourists visiting the sprawling temple complex have been caught without their clothes.
Three French tourists were deported last weekend after they pleaded guilty to taking nude pictures of each other inside another temple within the complex.
The three deported French men received a suspended six-month prison sentence on two charges - public exposure and making pornography - and will be banned from re-entering Cambodia for four years.
The trio were caught just days after a series of photos of Asian women posing nude at ancient Cambodian temples went viral online and outraged officials who vowed to step up efforts to prevent similar stunts.