During a recent regional screening program, 98 patients with a positive Hemoccult test were evaluated radiographically. Double-contrast barium enema (DCBE) detected all six carcinomas and 92% of 37 polyps. DCBE was also the most cost-effective procedure. Colonoscopy dramatically increased screening costs without providing evidence to support its use in all Hemoccult-positive patients. It is recommended that DCBE be the initial diagnostic test in Hemoccult-positive patients, to be supplemented in selected patients by flexible sigmoidoscopy or colonoscopy depending on the pathology evident on DCBE and on clinical circumstances.