Our objective was to analyze the survival of diabetic patients on renal replacement therapy and to compare their survival on extracorporeal and on peritoneal dialysis. All data regarding diabetic patients admitted to dialysis between 1 January 1983 and 31 December 1993 were collected by means of individual patient questionnaires sent to all of the 44 regional Renal Units (100% answers) of Lombardy, Italy. Cox proportional hazards model, stepwise procedure, was applied in order to select the covariates significantly associated with survival. Age (at baseline), sex, type of diabetes, initial modality of treatment (hemodialysis or peritoneal dialysis), and initial clinical risk factors (malignancies, serious heart disease, vascular disease, cirrhosis of the liver, cachexia) were considered. Descriptive analysis of survival was performed using the Kaplan-Meier technique. The survival of all diabetic patients (895) was 86.5% at one year, 52% at three years, and 34% at five years. The main causes of the 488 deaths of diabetic patients were cardiovascular diseases (56%), cachexia (18%), and infections (11%). The relative death risk of patients on peritoneal dialysis versus those on hemodialysis, after taking into account the main comorbid conditions, did not significantly differ from 1, as estimated by the Cox proportional hazards regression model. Five-year survival of diabetic patients was 34%, and no differences were found between peritoneal dialysis and hemodialysis as far as mortality is concerned.