Begun in 1979, the Italian CAPD Study Group monitored prospectively six years of CAPD experience (1980-1985) in 24 centers with 1107 end-stage renal disease (ESRD) patients (age 56.4 +/- 13.7 years). Compiled yearly, the clinical and therapeutical data were processed on a PDP 11-32 computer, according to UCLA BMPD-1L procedure. The survival rate was conditioned by age (more than 70) and by major clinical risk factors, with a large fraction of the deaths due to cardiovascular causes (40.6%) and cachexia (17.8%). The progressive reduction of peritonitis incidence (1/18.5 episodes/patient-month globally reached at the end of 1985) was due mainly to the wide spread adoption of the "Y" connection set (76% for 1985) and contributed to a decrease in drop-outs to 7.5% of 676 patients on CAPD during 1985.