14 insulin-dependent diabetic patients completed 122 patient months on continuous ambulatory peritoneal dialysis (CAPD), using only intraperitoneal insulin for glucose control. Survival was 70% at 1 year, in this relatively high-risk group, several members of which had been refused other modalities of treatment. Blood glucose control, using approximately 111 units of regular insulin per day intraperitoneally, was improved over pre-CAPD control, as assessed by monthly blood glucose determinations and Hgb A1c measurements. Pre-CAPD random blood glucose values fell in 13 of 14 from a mean of 367 +/- 42 to 207 +/- 15 mg/dl during CAPD. Mean pre-CAPD Hgb A1c levels were 14.2% with a fall to 10.5-11.4% during CAPD. The intraperitoneal insulin dose represented approximately 3.5 times the pre-CAPD total daily subcutaneous dose of insulin, and no patient required less than approximately twice the pre-CAPD insulin dose. Peritonitis rates were no different when compared to the general nondiabetic population on CAPD (269 patient months), and complicated episodes tended to be less frequent in diabetic patients. Intraperitoneal insulin administration is an effective means of controlling blood sugar in diabetics on CAPD, and does not increase the risk of infection.