The influence of gonadectomy on some variables related to the diabetic syndrome was studied in the eSS line of rats, a nonobese model of spontaneous non-insulin-dependent diabetes, whose biochemical and histopathological manifestations are more severe in males than in females. Rats were gonadectomized at 90 days of age. Spayed animals showed higher body weight, impaired intolerance to glucose at 9 and 12 months of age, lower insulinemia and a decreased number of large pancreatic islets. Castrated rats revealed lower body weight when compared with controls. However, those males did not evidence impairment in the intolerance to glucose, changes insulinemia or remarkable modifications in endocrine pancreas histology. In kidneys, a lower cellular area in superficial proximal convoluted tubules was noticed. Despite the lower biomass registered in orchidectomized animals, their diabetic evolution was not modified. Conversely, ovariectomy appeared to be a worsening factor.