Abstract: Endocrine changes were determined in 28 young patients with schistosomiasis dwar-fism, including 15 girls and 13 boys, with an average age of 16.4 years. Testosterone and estradiol concentrations of male patients were significantly lower than the control values. Testosterone concentrations of female patients were significantly higher than the control values. Estradiol concentrations were lower than normal levels, without statistical significance. LH, F, T, GH concentrations in all patients were within normal limits. LH responses to LRH agonist analogs were abnormal in 2/6 of female patients and 5/7 of male patients. Insufficient synthesis and secretion of somatomedin is probabaly responsible for disturbances of bone and sex ual development. The endocrine function in schistosomiasis dwarfism is different to a certain extent from that in pituitary dwar-fism.