Fourteen juvenile-onset diabetic patients accepted for renal transplantation and maintained on chronic peritoneal dialysis during a 3-year period were compared with a similar group of 43 patients accepted for renal transplantation and maintained on hemodialysis. The 1-year survival in each group was similar (52% on chronic peritoneal dialysis; 55% on hemodialysis), but there was a striking difference in progressive morbidity. Seven patients on chronic peritoneal dialysis were blind in one or both eyes at the onset, and visual acuity improved in two, including one bilaterally blind patient who achieved 20/35 vision bilaterally; none worsened. In the hemodialysis group, 12 patients were totally blind in one or both eyes and 11 additional patients became blind or had severe deterioration in vision; none improved. Neuropathy progressed in only 1 patient on chronic peritoneal dialysis, whereas it worsened in 17 patients on hemodialysis--9 to the extent that they needed braces or canes or were nonambulatory. All patients on chronic peritoneal dialysis were home trained and were dialyzed at night, with seven being able to work full or part time; virtually none of the patients on hemodialysis were able to work. Chronic peritoneal dialysis was relatively free of technical complication, and no significant difficulty was encountered in diabetic control, in the anephric state, or during abdominal surgery. Chronic peritoneal dialysis appears to have less associated morbidity than does hemodialysis in the treatment of chronic renal failure of juvenile-onset diabetes mellitus.