Survival rates, renal function, and histopathology were evaluated in 49 prospectively followed patients transplanted under 5 years of age at our center. Most patients (84%) suffered from congenital nephrosis of the Finnish type. Triple immunosuppression with cyclosporine administered in three daily doses to pre-school children was used. Patient survival 7 years after transplantation was 98% and graft survival 88%. All graft losses were due to post-transplantation nephrosis. The proportion of pathological findings in the follow-up biopsies did not change substantially with time. Five years after transplantation, 47% showed a normal histology and after 7 years this rose to 67%. Mean glomerular filtration rate (GFR) was 68 and 55 ml min per 1.73 m2 5 years and 7 years, respectively, after transplantation. The decline in GFR with time was significant. We conclude that good long-term results can be achieved with individually tailored triple immunosuppression in the youngest age group, even with cadaveric donors.