Abstract: Sporocysts of Sarcocystis suihominis collected from feces of infected persons who had ingested raw pork were used to infect swines. On the 56th day post inoculation, cysts were found in the cardiac and skeletal muscles. The cysts are spindle-like, elongated or elliptic. The cyst wall had numerous thick, villi-like projections and the cysts wera divided into many compartments by septa formed from the cyst wall. Each compartment was filled with banana-like bradyzoites, measuring 10.46×4.61 μm. Some of the cysts-had spherical or spheroidal metrocysts.Five rhesus monkeys fed raw pork containing S. suihominis cysts were not infected, while another monkey which had received hydrocortisone injection two days before S. suihominis intubation for 5 days voided sporocysts from feces on the eleventh day post inoculation for a period of 9 days. The sporocysts measured 12.72×10.24 μm.