The present report summarizes the mechanical and infectious complications attributable to the devices and procedures used for chronic peritoneal dialysis (PD), comparing the type and frequency of such complications in contemporaneous groups of patients undergoing continuous ambulatory PD (CAPD) or intermittent PD (IPD). Mechanical complications related directly to the catheter and its placement proved to be equally frequent during CAPD and IPD. On the other hand, mechanical complications related to increased intraperitoneal pressure were more frequent during CAPD. In most instances mechanical complication can be managed without permanent interruption of chronic PD. Peritonitis occurs more frequently during CAPD (1.6 episodes per patient-year) than during IPD (0.4 episodes per patient-year), with a tendency to more frequent peritonitis among diabetics, children, patients with white blood cell abnormalities, patients with catheter cuff or tunnel inflammation, and during the 1st month of treatment. Medical therapy eradicates peritonitis and allows continuation of chronic PD with retention of the catheter in more than 90% of episodes, although special problems may be encountered with fungal, pseudomonal, and some coagulase-positive staphylococcal infections.