From March 1987 to August 1990 23 cadaveric renal transplants were performed in 19 children under the age of 5 years at the time of transplantation. The mean age of the recipients was 3.3 years (range 1.3-4.7) and the mean weight 13.0 kg (range 9.3-19.2). The mean donor age was 7.8 years (range 1.5-25). All children received triple immunosuppression with prednisolone, cyclosporin A and azathioprine, and 4 who had 2 grafts during this period also received antithymocyte globulin at the time of the second transplant. Patient survival is 100%. Actuarial first cadaveric graft survival was 57% at 1 year and remains unchanged at 3 years. There were 10 graft losses, 4 were associated with renal venous thrombosis without apparent rejection. Two were lost due to acute vascular rejection with associated renal venous thrombosis, and the remaining 4 losses followed cellular or chronic vascular rejection. The mean glomerular filtration rate +/- SD was 51.4 +/- 23.6 ml/min per 1.73 m2 (n = 11) at 1 year and 43.5 +/- 25.3 at 2 years (n = 6). The mean height standard deviation score improved from -2.2 +/- 1.1 at the time of transplantation to -1.3 +/- 1.0 1 year post transplant (n = 11). The immunosuppression was well tolerated with a low incidence of side effects. Cadaveric renal transplantation remains a difficult but rewarding undertaking in children under 5 years of age.