A psoas abscess (PA) is a rare clinical entity but is potentially serious condition which presents diagnostic and therapeutic challenges. The diagnosis is frequently delayed due to its variable and nonspecific features and occult clinical course. The delay in diagnosis and treatment of PA is the major poor prognostic factor. We describe herein a case of the sterile psoas abscess complicating Cronh's disease which presented as hip flexion contracture. A 29-year-old man, at remission stage of CD involving ileocolic segment, was admitted due to pain from hip contracture. He had no bloody diarrhea and no abdominal pain. PA was confirmed by abdominal ultrasound. PA with hip contracture was completely treated with surgical excision, irrigation, drainage, and antibiotics. PA was sterile and there was no evidence of a fistulous communication from the bowel. Once suspected, aggressive diagnostic work up and definitive operative intervention is needed.