Objective: To elucidate hormonal disturbances in patients with type 1 diabetes mellitus (DM1) with and without growth retardation. Methods: Patients with DM1 were divided into two groups, group A consisted of 14 patients with poor growth, and group B consisted of 24 patients with normal growth. Serum IGF-I, IGFBP-3, basal and stimulated GB, and HbA1c were measured. Results: Serum IGF-I and IGFBP-3 concentrations were significantly decreased in group A versus both groups B and controls in Tanner stages I-III; in addition, these measurements in group B were significantly lower compared to controls in Tanner stages II and III, but there was no significant difference in prepuberty. Both basal and peak serum GH were attenuated significantly in group A versus group B. Basal serum GB in group B (normal growth DM1) was significantly elevated versus the controls. There was an unambiguous negative linear regression between IGF-I and mean HbA1c in patients with DM1. Conclusions: Growth retardation in patients with DM1 is associated with an abnormal GB-IGF-I axis and poor glycemic control. © Freund Publishing House Ltd., London.