Sarcocystosis is caused by species of Sarcocystis, an intracellular protozoan parasite in the phylum Apicomplexa. These parasites have an indirect life cycle, cycling between a definitive and an intermediate host. Intestinal infections occur in the definitive host, and tissue invasion is seen in the intermediate host. In this study, heart and diaphragm muscles of 60 sheep were collected from Tabriz abattoir and assessed for the presence of S. tenella using methods of impression smear, tissue digestion, and PCR-RFLP techniques. Microscopic cysts was identified by preparation of direct tissue impression smears from samples and staining them by Giemsa stain and digestion of samples by pepsin and finally centrifugation and preparation of smear from the sediment and staining them with Giemsa stain. We found the microscopic cysts in 40 % of impression smears and 100% of tissue digestions. We observed S. tenella in 70% of muscle samples by using of PCR-RFLP method. This study showed that tissue digestion method is more sensitive method for Sarcocystis. PCR-RFLP technique by use of specific primers and TAG1 enzymes is shown to be an easy and rapid method for identification of species.