Eleven boys, mean age 15.3 years (range 13.2-17.5), with pubertal delay in association with steroid therapy for steroid-sensitive nephrotic syndrome and following renal transplantation were treated with oxandrolone 2.5 mg daily for a mean of 0.50 years (range 0.34-0.61). Mean growth velocity increased from 3.9 cm/year (range 1.1-6.3) to 6.1 cm/year (range 2.0-14.4) and was maintained at 6.1 cm/year (range 0.4-10.2) (P less than 0.05). However, there was no significant difference in growth between the treated boys and age- and puberty-matched controls. Elevation of blood cyclosporin A and creatinine levels occurred in the transplant patients. Oxandrolone may initiate a pubertal growth spurt in patients taking steroid therapy for renal disease, but should be used with extreme caution because of potential side-effects.