Background and objectives Few studies have evaluated vascular access use after transition from peritoneal dialysis to hemodialysis. Our study characterizes vascular access use after switch to hemodialysis and its effect on patient mortality and evaluates whether a peritonitis event preceding the switch was associated with the timing of permanent vascular access placement and use. Design, setting, participants, & measurements The US Renal Data System data were used to evaluate the establishment of a permanent vascular access in 1165 incident Medicare–insured adult patients on dialysis who initiated peritoneal dialysis between July 1, 2010 and June 30, 2011 and switched to hemodialysis within 1 year. Results The proportions of patients using a hemodialysis catheter were 85% (744 of 879), 76% (513 of 671), and 51% (298 of 582) at 30, 90, and 180 days, respectively, after the switch from peritoneal dialysis to hemodialysis. Patients who switched from peritoneal dialysis to hemodialysis with a previous peritonitis episode were more likely to dialyze with a catheter at 30 days (90% [379 of 421] versus 80% [365 of 458]; P=0.03), 90 days (82% [275 of 334] versus 71% [238 of 337]; P=0.03), and 180 days (57% [166 of 289] versus 45% [132 of 293]; P=0.04) after the switch and less likely to dialyze with an arteriovenous fistula at 30 days (8% [32 of 421] versus 16% [73 of 458]; P=0.01), 90 days (13% [42 of 334] versus 23% [76 of 337]; P=0.03), and 180 days (31% [91 of 289] versus 43% [126 of 293]; P=0.04). Patients using a permanent vascular access 180 days after switching from peritoneal dialysis to hemodialysis had better adjusted survival during the ensuing year than those using a catheter (hazard ratio, 0.66; 95% confidence interval, 0.44 to 1.00; P=0.05). Conclusions Among patients who switch from peritoneal dialysis to hemodialysis, prior peritonitis is associated with a higher rate of persistent hemodialysis catheter use, which in turn, is associated with lower patient survival. Studies addressing vascular access planning and implementation are needed in this group of patients.