Spontaneous cardiomyopathy or round heart disease of turkeys was noticed in the imported breeds of heavy broad-breast turkey poults breed (B6 & T9). Most deaths from the disease were detected during the first 3 weeks of life. The mortality rate was ranged from 5 to 15 %. The most striking and consistent lesion found at necropsy was enlargement and distortion of the heart due to dilatation of both ventricles. Ascites and hydropericardium were present in some cases. Lungs were congested and edematous. The liver, intestine, spleen and kidneys occasionally showed evidence of congestion. Microscopically, congestion, degeneration and vacuolation of myofibers resulting in damage and disappearance of some muscle fibers were markedly seen in the heart. The livers of the affected turkeys revealed portal fibrosis, bile ductal hyperplasia, hepatocytic vacuolation and intracytoplasmic eosinophilic globules in the hepatocytes. The histopathological changes in the lungs, intestine, spleen, kidneys and brain were also recorded. Moreover, the pathogenesis of the condition in relation to the pathological findings was discussed.