Tumor Necrosis Factor alpha plays a main role in ulcerative colitis. Thirteen male and 8 female affected by moderate to severe steroid-dependent or refractory-severe ulcerative colitis were treated with 5 mg/kg of infliximab (Remicade). At 12 week efficacy, steroid-sparing, colectomy and side effects were evaluated. In steroid-dependent group (13 patients): 8 patients had a clinical benefit (7 obtained a clinical remission, 54%), 8 (61.5%) discontinued steroids, 1 patient underwent surgery. In steroid-severe refractory group (8 patients): 3 patients (37.5%) had a clinical remission, 2 (25%) had a clinical response and 3 (37.5%) underwent colectomy. One mild infusion reaction and one adverse event (itch) were observed. Infliximab is an effective and safe therapy in patients with moderate to severe steroid dependent and refractory ulcerative colitis.