Background: Sarcopenia has been proposed to be a prognostic factor of outcomes for various diseases but has not been applied to Crohn's disease (CD). We aimed to assess the impact of sarcopenia on postoperative outcomes after bowel resection in patients with CD. Materials and Methods: Abdominal computed tomography images within 30 days before bowel resection in 114 patients with CD between May 2011 and March 2014 were assessed for sarcopenia as well as visceral fat areas and subcutaneous fat areas. The impact of sarcopenia on postoperative outcomes was evaluated using univariate and multivariate analyses. Results: Of 114 patients, 70 (61.4%) had sarcopenia. Patients with sarcopenia had a lower body mass index, lower preoperative levels of serum albumin, and more major complications (15.7% vs 2.3%, P = .027) compared with patients without sarcopenia. Moreover, predictors of major postoperative complications were sarcopenia (odds ratio [OR], 9.24; P = .04) and a decreased skeletal muscle index (1.11; P = .023). Preoperative enteral nutrition (OR, 0.13; P = .004) and preoperative serum albumin level >35 g/L (0.19; P = .017) were protective factors in multivariate analyses. Conclusion: The prevalence of sarcopenia is high in patients with CD requiring bowel resection. It significantly increases the risk of major postoperative complications and has clinical implications with respect to nutrition management before surgery for CD.