Abstract: Enterotoxaemic diseases, are the most important diseases caused by C. perfringens in ruminants. Ovine enterotoxaemia is of economic importance and has been reported to be produced by all five toxinotypes of C. perfringens (A through E) on the basis of its capability to produce major lethal toxins (alpha, beta, epsilon and iota toxins). Although, C. perfringens type D has been reported to be the dominant type causing enterotoxemia in sheep in Iran. This study was carried out, in the Northwestern of Iran to assess the distribution of Enterotoxemia and its prevalence rate in sheep at spring 2008. A total of 87802 sheep and lambs, belonging to 38 different large sheep farming zones, with size ranging from 200-8600 sheep from suburb of ten towns of East Azerbaijan province, were examined. The prophylaxis of enterotoxaemia in the animals was achieved by vaccination. Diagnoses of the disease were mainly based on the clinical examinations and classical bacteriological methods. Only in 128 (0.14%) animals with clinical signs of enterotoxemia including sudden death or abnormalities in digestive and/or nervous systems, C. perfringens were identified by classical bacteriological examinations. The average case fatality rate in this study was 40% (51/128) and the case fatality rates in each flock ranged between 0 and 80%. Prevalence rates in flocks of Ahar, Shabestar and Heris were highest in this study. No significant histological changes were found in the small or large intestine of any of the animals dying from enterotoxemia. Although, with the exception of only 2 animals that showed renal cortical hemorrhages, neither gross nor histological changes were observed in the kidneys of the animals that were necropsied immediately after death. These results suggested that the prevalence rate of enterotoxemia in sheep in East Azerbaijan province at last spring season was relatively low. However, it is strongly recommended that a regular vaccination schedule should be continued to prevent the occurrence of enterotoxemia in the province.