Linear growth is more often impaired after liver than after renal transplantation (Tx) in childhood. As similar triple immunosuppression was used in our liver and renal transplant recipients, we were able to compare growth and endocrine function between 19 prepubertal liver and 35 renal transplant recipients. There were no significant differences in median age, weight-for-height index, or height standard deviation score at Tx. Seventy-eight percent of the liver Tx patients, but only 7% of the renal Tx patients, were below the normal range for height 3 years after Tx. Graft function was good in both liver and renal transplant recipients 3 years after Tx. There was no significant difference in growth hormone secretion, serum insulin-like growth factor (IGF)-I, and IGF-binding protein-3 levels, or in methylprednisolone and cyclosporine doses. However, the blood cyclosporine levels were significantly higher in the liver transplant recipients (P = 0.001 1 year and P = 0.005 2 years after Tx). Cortisol production was significantly lower in the liver transplant recipients (P = 0.002 1 year and P = 0.049 2 years after Tx), which suggests greater steroid-mediated suppression of adrenal function. Growth inhibition is more often observed in liver than in renal transplant recipients on similar triple immunosuppression, and may not be related to deficient function of the growth hormone-IGF-I axis. Similar cyclosporine doses result in higher plasma levels of the drug and similar methylprednisolone doses result in more inhibited adrenal cortisol production in liver transplant recipients. In children with organ transplants, cyclosporine and methylprednisolone should be administered on an individual basis.