Twenty living kidney donors with schistosomiasis were compared with 20 uninfected donors for a mean follow-up period of 42 months (range 12-62). All patients with schistosomiasis had been treated preoperatively with antischistosomal chemotherapy. None of the donors developed any appreciable change in mean systolic or diastolic blood pressure during the follow-up period, though one infected and two uninfected donors had traces of protein in the urine. One uninfected donor developed microscopic haematuria. The two groups has similar reductions in renal function after unilateral nephrectomy. The response of the remaining kidneys to a combined infusion of dopamine and an amino acid preparation was similar in both groups. One infected and two uninfected donors were found to have developed mild hydroureter and hydronephrosis on excretory urography. Schistosomiasis did not significantly affect compensatory hypertrophy of the remaining kidney. We conclude that uncomplicated schistosomiasis in living kidney donors does not adversely affect either the function or the morphology of the remaining kidney, at least during an observation period of up to five years. Schistosomal infection does not seem to alter the adaptive changes in the remaining kidney, provided that the donor had functionally and morphologically intact kidneys and that the schistosomiasis was treated before kidney donation. Longer term evaluation is recommended, however, to confirm the validity of these observations.