Crohn's disease (CD) is an inflammatory bowel disease whose precise etiology is still unknown, and therefore a causal therapy is not yet available. Studies showing the overexpression of IL-12 and IL-23, polymorphisms in genes encoding those cytokines and their receptors and genome-wide association studies have linked Crohn's pathogenesis with IL-12/23 pathway. Ustekinumab is a novel therapeutic IgG₁ kappa monoclonal antibody that modulates Th1 and Th17 function, by blocking the p40 subunit of both IL-12 and IL-23 and preventing the interaction with their receptors on T cells, natural killer cells and antigen-presenting cells with established efficacy in psoriasis. This review will mainly focus on the available evidence on the role of ustekinumab in moderate-to-severe CD. The potential role of this biologic in the armamentarium of CD therapy is discussed.