The purpose of this study was to evaluate and compare the effects of formocresol (FC), ferric sulfate (FS), white mineral trioxide aggregate (WMTA), white Portland cement (WPC), and beta-tricalcium phosphate (beta-TCP) on pulpotomized primary teeth of pigs. Fifty teeth of three 3-month old pigs were pulpotomized with these materials. Three weeks later, the animals were euthanized and the specimens were prepared for histological examination. There was no significant difference between beta-TCP, WMTA, and WPC in terms of primary pulp response, hard tissue formation, and normal pulp tissue preservation. But, both FS and FC irritated the pulp tissue, provoking a more inflammatory pulp response than beta-TCP, WMTA, and WPC. Beta-TCP, WMTA, and WPC are histologically more effective pulpotomy agents than formocresol and ferric sulfate in primary pig teeth.