Anti-tumor necrosis factor (anti-TNF) agents are widely used in the treatment of moderate to severe ulcerative colitis (UC) since commercial approval in 1998. Many patients however ultimately require surgery with ileal pouch-anal anastomosis (IPAA). Conversion of UC to Crohn’s disease (CD) following IPAA is a devastating complication termed de novo Crohn’s disease (DNCD). Despite increasing adoption, few prior studies have evaluated the effect of preoperative anti-TNFs on DNCD development. As we have noticed an increasing incidence of DNCD, we hypothesized that preoperative utilization of anti-TNFs may be associated with the development of DNCD after IPAA.