Background Several reports on patients with diabetes mellitus (DM) treated by peritoneal dialysis (PD) have shown a higher risk of PD-associated peritonitis compared to non-DM (NDM) patients. The aim of this study was to investigate the incidence of PD-associated peritonitis in DM patients. Methods We divided all patients who received PD at a single center between January 1980 and December 2012 into three groups according to era: Period 1 (n = 43, 1980-1993); Period 2 (n = 123, 1994-2004); and Period 3 (n = 207, 2005-2012). We investigated incidences of PD-associated peritonitis between patients with and without DM. Results In Periods 1 and 2, incidence of PD-associated peritonitis was higher in the DM group than in the NDM group (P Conclusions The increased risk of peritonitis in diabetics reported in previous periods has not been evident in recent years.