Patients affected by Crohn's disease (CD) require lifelong medical therapy, but they can also often require abdominal surgery. The effect of CD therapy on postoperative course is still unclear. The aim of this study was to evaluate the effect of preoperative medical therapy on the outcome of intestinal surgery in these patients. Data from a consecutive series of 167 patients with CD operated on at the University of Padova Hospital from 2000 to 2013 were retrieved. Data of preoperative therapy during the 6 months before surgery were available for 146 patients who were enrolled in this retrospective study. Clinical data and surgical details were retrieved and postoperative complications and reoperation were considered outcome measures. Univariate and multivariate analysis were performed. No significant difference was observed between patients without data about their preoperative therapy and those with them. Eight patients underwent reoperation in the first 30 postoperative days: two of them for anastomotic leak, three for bleeding, one for obstruction and two for abdominal wound dehiscence. At multivariate analysis, preoperative adalimumab and budesonide resulted to be an independent predictor of reoperation (OR = 7.67 (95% CI = 1.49-39.20), p = 0.01 and OR = 6.7749 (95% CI = 0.98-46.48), p = 0.05, respectively). At multivariate analysis neither pharmacological nor clinical variables resulted to predict anastomotic leak. In our series, adalimumab seemed to be associated to early reoperation after intestinal surgery. This may be due to a worst disease severity in patients who needed surgery in spite of biological therapy. Preoperative tapering of budesonide dose seems a safe option before elective abdominal surgery for CD.