The treatment of end-stage renal failure by continuous ambulatory peritoneal dialysis has proven less successful than anticipated due to the high incidence of infective peritonitis. Essentially, peritoneal host defenses are critically immunocompromised by the presence of two foreign bodies: dialysate and Tenckhoff catheter. Thus, infection is readily established and is frequently impossible to eradicate despite appropriate antibiotic therapy. It follows that the prevention of infective peritonitis is of supreme importance to the success of the technique. Recent research into the epidemiology and pathogenesis of infections caused by the most important groups of infecting microorganisms has demonstrated that this goal is achievable.