A recent study of 10 men with postpolio syndrome indicated a low secretion of growth hormone (GH) as reflected by serum insulin-like growth factor-I (IGF-1). Therefore, 87 patients were studied, 17 to 71 years after acute poliomyelitis, of whom 65% reported the occurrence of new or increased weakness (ie, during the last 2 years) in muscles previously affected by polio. Serum IGF-1 concentrations in the patients were compared with those found in a reference population comprising 392 randomly selected individuals. No differences from the reference population values were observed. No correlation was found between IGF-1 concentrations and the severity of the original polio affliction, the recovery status, the need for ambulation aids, or the presence of new symptoms. The results do not indicate a need for GH substitution treatment of patients with postpolio syndrome.