BACKGROUND AND AIM: Ustekinumab (UST), a fully humanized monoclonal antibody against the p40 subunit of interleukin-12/23, is effective for the treatment of Crohn's disease (CD). The benefit of concomitant use of an immunomodulator (IM) with UST, however, is unclear. This study aimed to provide a systematic review and meta-analysis comparing the efficacy and safety of concomitant use of an IM with UST as an induction therapy for CD patients. METHODS: A systematic literature search was performed using PubMed/MEDLINE, the Cochrane Library, and the Japana Centra Revuo Medicina from inception to October 31, 2019. The main outcome measure was achievement of clinical efficacy (remission, response, and clinical benefit) at 6-12 weeks. The quality of the included studies was assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tools. The fixed-effects model was used to calculate the pooled odds ratios. RESULTS: From 189 yielded articles, six including a total of 1507 patients were considered in this meta-analysis. Concomitant use of an IM with UST was significantly effective than UST monotherapy as an induction therapy (pooled odds ratio in the fixed-effects model: 1.35, 95% confidence interval [1.06-1.71], P = 0.015). The heterogeneity among studies was low (I  = 2.6%). No statistical comparisons of the occurrence of adverse events between UST monotherapy and concomitant use of an IM with UST were performed. CONCLUSION: The efficacy of concomitant use of an IM with UST as an induction therapy for CD was significantly superior to that of monotherapy with UST.