Posttransplant diabetes mellitus is ascribed to the use of corticosteroids. Because use of cyclosporine has been associated with increased rates of posttransplant diabetes mellitus, risk factors for this condition have been studied in adults and found to include older age, excessive body weight, and a family history for non-insulin-dependent diabetes mellitus. Only about 1% of children develop diabetes mellitus after transplant surgery. A study of pediatric transplant recipients with diabetes mellitus and of pediatric renal transplant recipients suggested that posttransplant diabetes mellitus may be more common in children with risk factors and may reveal types of diabetes which are infrequent in childhood, e.g., non-insulin-dependent diabetes mellitus which would have gone undiagnosed until adulthood in the absence of corticosteroid therapy. In contrast, corticosteroids apparently had little influence on glucose tolerance in subjects free of risk factors. The effect of corticosteroids seemed to be somewhat less marked than that of renal function impairment.