We analyzed data from the Australia and New Zealand Dialysis and Transplant Registry for 1 October 2003 to 31 December 2008 with the aim of describing the nature of peritonitis, therapies, and outcomes in patients on peritoneal dialysis (PD) in Australia. At least 1 episode of PD was observed in 6639 patients. The overall peritonitis rate was 0.60 episodes per patient–year (95% confidence interval: 0.59 to 0.62 episodes), with 6229 peritonitis episodes occurring in 3136 patients. Of those episodes, 13% were culture-negative, and 11% were polymicrobial. Gram-positive organisms were isolated in 53.4% of single-organism peritonitis episodes, and gram-negative organisms, in 23.6%. Mycobacterial and fungal peritonitis episodes were rare. Initial antibiotic therapy for most peritonitis episodes used 2 agents (most commonly vancomycin and an aminoglycoside); in 77.2% of episodes, therapy was subsequently changed to a single agent. Tenckhoff catheter removal was required in 20.4% of cases at a median of 6 days, and catheter removal was more common in fungal, mycobacterial, and anaerobic infections, with a median time to removal of 4 – 5 days. Peritonitis was the cause of death in 2.6% of patients. Transfer to hemodialysis and hospitalization were frequent outcomes of peritonitis. There was no relationship between center size and peritonitis rate. The peritonitis rate in Australia between 2003 and 2008 was higher than that reported in many other countries, with a particularly higher rate of gram-negative peritonitis.