330 Samples of the slaughtered cattle heart muscle were collected from the abattoirs of five regions in Kangwon - do to reveal the frequency of sarcocystis infections during January through December in 1991. The samples were inspected for bradyzoites by the trypsin digestion technique and the possitive samples were fed to dogs and cats for the detection of sporocysts shed in the feces. The results obtained were summarized as follows : 1. The infection rate of bovine Sarcocystis investigated from 330 samples was 43.6%. 2. It revealed that the infection rate of Sarrocystis increased gradully with the advance in the age, 14.5% in below two years, 26.1% in the three years, 30% in four years, 54.7% in five years, 74.4% in six years, 90% in seven years and 100% in older than eight years. 3. The cyst walls detected out from the heart muscles were less than l${mu}{ extrm}{m}$ in thickness and the size of bradyzoites were $11.8{ imes}2.8{mu}m$ in average. 4. The size of sporocysts shed in the feces of dogs were $15.8{ imes}9.8{mu}m$ in average and the prepatent periods ranged from 12 to 16days. 5. Sarcorystis found in the bovine heart muscles were identified as Sascocystis cruzi ( Hasselman, 1923) , wenyon, 1926.