We treated a 57-year-old woman for refractory inflammatory bowel disease with a humanized anti-tumor necrosis factor alpha monoclonal antibody (Infliximab). The patient also had a 15-year history of Crohn's disease and a 20-year history of moderate to severe psoriasis. She received a single infusion of Infliximab (5 mg/kg). Two weeks after the infusion her psoriasis had dramatically improved in appearance. To our knowledge, our case is the first reported instance of successful anti-tumor necrosis factor alpha therapy in psoriasis.