Psoas abscesses are rare clinical entities complicating Crohn's disease (CD). However, psoas abscesses can cause poor outcomes because the diagnosis is frequently delayed due to the non-specific clinical features. Recently, we managed a case of a huge iliopsoas abscess in a 21-year-old man with a 4-year history of CD who presented with a limping gait and flexion contractures of the sacroiliac joint. Notably, the iliopsoas abscess developed during induction treatment with infliximab. The patient was successfully treated with antibiotics, surgical drainage, and a right hemicolectomy. Herein we present the case with a brief review of the literature. (Intest Res 2009;7:118-122)