A continent Kock ileostomy was constructed in 17 patients with histologically proven ulcerative colitis; in 11 a conventional ileostomy was converted to a Kock ileostomy and in 4 the Kock ileostomy was carried out in conjunction with proctocolectomy. There were no operative deaths. All patients are completely continent with regard to flatus and stool. No patient requires an external appliance and all agree that the quality of their lives has greatly improved. However, 10 patients (59%) required at least one additional surgical procedure for early or late complications, the most frequent of which were intestinal obstruction and valve slipping. In an attempt to reduce morbidity, several technical modifications were made. The preliminary results of the modified techniques used in 17 patients are described. The benefits of the continent ileostomy are substantial despite the high initial morbidity. The authors recommend the use of the continent ileostomy in selected patients.