The function of 20 human autologous kidney grafts was studied for 4 to 8 years (mean 5 1/2) after autotransplantation with a direct pyelocystostomy. The indications for the operation were low-grade, low-stage tumour of the renal pelvis and/or ureter, frequently recurrent renal stones and remaining outflow obstruction after pyeloplasty for hydronephrosis. The wide pyelocystostomy implies reflux of urine from the urinary bladder to the renal pelvis but no significant changes were found in glomerular or tubular function, studied with 51Cr-EDTA clearance, 131I-Hippuran renography, analysis of beta 2-microglobulin and total protein excretion in urine, and determination of concentration ability after administration of desmopressin. No increase in the severity or frequency of urinary tract infections was observed.