Clinical course, complications and outcome were analyzed in 75 patients (14 women, 61 men) who started CAPD at age 55 years or older (55-81). These patients were separated in three groups. Group A patients had high risk for vascular disease (diabetes, hypertension, N = 45), group B patients had a presumed lower risk for vascular disease (primary renal disease, N = 22), and group C patients had miscellaneous conditions (N = 8). Group A was compared to group B. Patient and technique survival was statistically higher for group B than for group A. The rates of peritoneal dialysis related complications (peritonitis, tissue infections, catheter loss, hernias) were comparable between groups A and B. Hernias were seen frequently in all groups and had severe sequellae, including discontinuation of CAPD. Catastrophic vascular events were also seen in all groups, but the frequency of such events, particularly of catastrophic vascular events of the limbs, was statistically higher in group A than in group B. Vascular disease accounted for the majority of deaths in all groups. Four patients died from cardiovascular instability soon after changing from CAPD to hemodialysis. In conclusion, vascular disease is the major factor limiting survival in older CAPD patients. CAPD is superior to hemodialysis for a relatively small fraction of older patients with severe cardiovascular instability.