Loop ileostomy to establish fecal diversion has been used in 79 patients as the initial surgical procedure in severe, debilitating Crohn's colitis or ileocolitis. Clinical improvement, as measured by subjective and objective criteria and length of hos-pitalization, occurred in 72 of 79 patients (91%). Definitive surgery was then undertaken at a later stage under more ideal circumstances without mortality. The high relapse rate of 33% in this series would lead us to recommend definitive surgery electively at an early stage after initial clinical improvement. Four of the 79 patients in this series died; three deaths were related to Crohn's disease, for a total mortality of 5.1%. It is believed that loop ileostomy to establish fecal diversion has a definite role in the initial surgical management of the severely ill patient with Crohn's colitis.