Chow Hok Kuen, 28, who is of Taiwanese origin, was arrested with the grisly haul in the city's Chinatown on Thursday, police said. The corpses had been packed into luggage and were set to be smuggled to Taiwan.
The suspect bought the foetuses several days ago from a Taiwanese man in Thailand for 200,000 baht ($6,500) and planned to sell them in Taiwan for up to six times that amount, police said. The origin of the foetuses was unclear.
"He said he planned to sell the foetuses to clients who believe they will make them lucky and rich," said Colonel Wiwat Kamchamnan of Bangkok police.
The man faces one year in prison and a 2,000 baht fine for possession of the foetuses.
In Thai black magic rituals, also observed among some Chinese communities, preserved foetuses are believed to bring good fortune to the owner and are often kept in shrines within homes or businesses.