["Infliximab and adalimumab are increasingly used to prevent postoperative recurrence in Crohn's disease patients. The impact of previous exposure to one or more anti-tumour necrosis factor [TNF] agents before surgery on the efficacy of anti-TNF therapy on postoperative recurrence is unknown.", "We performed a retrospective analysis of Crohn's disease patients who underwent surgical bowel resection with anastomosis and prophylactic treatment with anti-TNF therapy between January 2005 and June 2013.", "A total of 57 consecutive Crohn's disease patients with bowel resection and anastomosis followed by prophylactic treatment with anti-TNF were included; 21 [37%] and 24 [42%] patients had a previous exposure to one and more than one anti-TNF agents, respectively; 39 patients [68%] had a surveillance colonoscopy. Cumulative rates of postoperative endoscopic recurrence at 2 years were 45.5% [26.6-69.6%] in patients exposed to two or more anti-TNFα as compared with 29.1% [11.5-48.1%] in patients exposed to one or to zero anti-TNFα before surgery [p = 0.07]. Cumulative rates of clinical recurrence at 1 year were 21.6% [9.6-44.4%] in patients exposed to two or more anti-TNFα as compared with 6.9% [1.8-25.1%] in patients exposed to zero or one anti-TNFα before surgery [p = 0.02]. Multivariable analysis identified smoking and previous exposure to two or more anti-TNFα as risk factors for Crohn's disease clinical or endoscopic postoperative recurrence (hazard ratio [HR] = 3.17; 95% confidence interval [CI]: 1.3-7.8, p = 0.01 and HR = 4.2; 95% CI: 1.8-10.2, p = 0.001, respectively)."] Does previous Exposure to Multiple Anti-TNF be Associated with Decreased Efficiency in Preventing Postoperative Crohn 's Disease Recurrence?