Ustekinumab is approved for the treatment of psoriasis in adolescents and for the treatment of moderate to severe Crohn's disease (CD) in adults, but data are lacking in pediatric CD. We report a case of severe psoriasis induced by biotherapies in an adolescent with CD that improved after switching to ustekinumab (90 mg at weeks 0, 2, and 4 and then every 8 weeks). The patient had not experienced CD relapse after 1 year of follow-up. Ustekinumab can be an alternative therapy for psoriasis induced by biotherapies when conventional treatment fails and can maintain remission of CD.