Serum concentrations of testosterone and dehydroepiandrosterone sulphate (DHAS) have been measured in 10 stable insulin-dependent diabetic (IDD) males (chronological age (CA) range 13·0-17·5 years). Their results have been compared with those of a control population of 69 non-diabetic males who presented with mild constitutional growth delay and whose skeletal maturity and pubertal development were similar to the diabetic subjects. Within bone ages (BA) 11·0–14·5 years no significant difference was observed between the serum testosterone concentrations of the diabetic patients and controls: diabetic males, 8·2 (0·3–25) nmol/1 (median and range); controls, 7·0 (< 0·3–23) nmol/1. In contrast, within BA 11·0–14·5 years, the diabetic males had significantly lower serum DHAS concentrations: diabetic males, 1·1 (0·7–4·2) μmol/1; controls, 3·7 (0·7–5·6) μmol/1 (P < 0·001). The serum DHAS concentrations of the diabetic males were also significantly lower than the controls when matched separately for pubic hair and genital development, testicular volume and serum testosterone, (in each comparison P < 0·02). Serum DHAS concentrations of the diabetic males did not correlate significantly with CA, BA, BA delay (CA-BA), age of onset of diabetes, duration of diabetes, or glycosylated haemoglobin (GHb), but significant correlation was observed between BA delay and duration of diabetes, r= 0·65, P < 0·05. We conclude that gonadarche appears to proceed despite delayed adrenarche in IDD males. This study presents further evidence in favour of adrenarche and gonadarche being independent physiological events. The causes and clinical significance of low serum DHAS concentrations in adolescent diabetic males remain to be established.