Perianal fistulas occur in approximately 30% of patients with Crohn's disease (CD). Infliximab, a chimeric monoclonal antibody targeting human tumor necrosis factor alpha (TNF), is approved for the treatment of fistulizing CD. Although the initial response to infliximab is dramatic, the median duration of fistula closure is approximately 3 months, and repeated infusions are often required. An exam under anesthesia (EUA) by a surgeon allows for complete inspection of the fistula as well as incision and drainage of an abscess and placement of a seton. Our aim was to compare the rate of perianal fistula healing, relapse rate, and time to relapse in patients with fistulizing CD treated with infliximab alone or as an adjunct to surgical EUA with seton placement. Thirty-two consecutive patients with perianal fistulizing CD who completed at least 3 infusions with infliximab (5 mg/kg at 0, 2, 6 weeks) between October 1999 and October 2001 were analyzed. All patients had at least 3 months of follow-up after the third dose of infliximab. Response was defined as complete closure and cessation of drainage from the fistula. Patients with CD and perianal fistulas who had an EUA prior to infliximab infusions had a better initial response (100% vs. 82.6%, p = 0.014), lower recurrence rate (44% vs. 79%, p = 0.001), and longer time to recurrence (13.5 months vs. 3.6 months, p = 0.0001) compared with patients receiving infliximab alone. In conclusion, patients with fistulizing CD treated with infliximab are more likely to maintain fistula closure if treatment is preceded by EUA and seton placement.