The Network Coordinating Council (NCC) #4 continuous ambulatory peritoneal dialysis (CAPD) study was designed to gather basic demographic information and analyze selected outcome parameters on all patients started on CAPD in Southern California/Southern Nevada. Between early 1979 and Dec 31, 1983, 775 patients were enrolled in the study for a total experience of 878.5 patient-years. Demographic data revealed 25% of patients were over 60 years old and 17.4% were less than 20 years old at the start of CAPD, 65% were white, and 28% had chronic glomerulonephritis as a cause of end-stage renal disease (ESRD). Compared to all NCC #4 patients on dialysis (hemo and peritoneal), the young (less than 20 years old) and whites were overrepresented on CAPD. Patient outcome was assessed by life table analysis which revealed 90%, 80%, 70%, and 70% patient survival at 12, 24, 36, and 43 months, respectively; and technique success of 80%, 60%, 48%, and 40% for the same time periods, respectively. Over half of the dropout from CAPD and one third of the hospitalizations were related to recurrent infection. Few patients transferred from CAPD because of dissatisfaction with the technique or because of peritoneal membrane failure. CAPD is an excellent form of therapy for ESRD that controls uremia adequately and improves the quality of life for many patients. Long-term application of CAPD is hampered, however, by the high frequency of recurrent infections.