EMG examination was performed in 41 patients with Chagas' disease, belonging to the several clinical forms of the disease. Constant and direct relationship between the amount of muscle skeletal denervation and the clinical forms has been shown. In addition light peripheral axonal neuropathy was seen. Both muscular and sensory denervation was intense in the group with cardio-digestive form, moderate in the groups with either cardiac or digestive form and light in the group with the indeterminate form. The severity of the clinical symptoms was not related with the amount of peripheral denervation.