Technical Abstract: Water buffaloes (Bubalus bubalis) are intermediate hosts for 4 species of Sarcocystis, i.e., S. fusiformis and S. buffalonis with cats as definitive hosts, S. levinei with dogs as definitive hosts, and S. dubeyi with an unknown definitive host, but thought to be zoonotic. Currently, the latter species has been identified with certainty only from Vietnam. In the present study, sarcocysts of S.dubeyi are reported in 11 (30%) of 35 Egyptian water buffaloes from which the esophageal muscles were examined histologically. Sarcocysts were microscopic, measuring 180 – 250 x 70 – 110 µm in size. Ultrastructurally, the sarcocyst wall was 3.5– 6.5 µm thick and had palisade-like villar protrusions, which give it the striated appearance. The villar protrusions contained microtubules that were distributed along the whole villus. This is the first report of S. dubeyi from water buffaloes in Egypt.