Background Crohn’s disease (CD) recurrence can occur not only at the site of anastomosis but also elsewhere in the bowel following an ileocolic resection (ICR) procedure. The aims of the present study were to assess long-term outcomes of a primary ICR procedure for CD in consecutive patients and examine the location of the reoperation causative lesion.Methods We examined cases of surgery with ICR initially performed at our institution. Those with simultaneous multiple bowel resection or bowel resection with strictureplasty were excluded. Results A total of 169 patients who underwent ICR due to CD were enrolled. The median follow-up period was 12.6 years (range 4-27 years). A reoperation was needed in 45 (26.6%), of whom 14 had lesions causative of the reoperation at other than the anastomotic site. The most common causative lesion location was in the colon rather than the oral side of the small intestine. Furthermore, we investigated the relationship between presence of residual lesions following the initial surgery and lesions causative of reoperation. In the group without residual disease (n=31), 29.0% (n=9) had non-anastomotic lesions involved in indications for reoperation, while that was 35.7% (n=5) in the group with residual disease (n=14).Conclusions Anastomotic site lesion is not the only causative factor for reoperation following ICR. Regular examinations and applicable treatment with awareness that the cause of reoperation is not limited to the site of anastomosis are important in these cases.