We established an open-access, flexible, fiberoptic sigmoidoscopy service in an outpatient clinic in Kiriat-Shmona, Northern Israel. Twenty-eight general physicians in the city and in 41 surrounding rural residences (population 40,000) were encouraged to refer patients for sigmoidoscopy. In the first operative year, flexible sigmoidoscopy was performed on 255 patients (age range 10-90 years, mean 54). The male to female ratio was 123:132; women were slightly older than men (mean age 55.9 years vs. 51.1). Rectal bleeding and change in bowel habits were the most common indications. The sidmoidoscope was passed to the splenic flexure in 156 patients (61%). In five patients (2%) the instrument could not be inserted beyond the rectosigmoid junction. Excluding hemorrhoids and anal lesions, abnormalities were detected in 69 patients (27%). In 29 patients (11.4%) a cancer or polyp was found. Analysis of referral indications showed an increased positive predictive value for neoplastic lesions in patients referred for anemia (22.2%), weight loss (20.0%), abdominal pain (17.8%), and positive fecal occult blood test (15.4%). There were only two patients with polyp or cancer of 55 (3.6%) < 40 years of age, in contrast to 27 of 200 (13.5%) > 40 (p < 0.05). Sixty-six patients underwent further investigation, and 26 had positive results: colonic lesions were confirmed in 20 patients, sigmoid colon cancer was found on barium enema in one, and lesions outside the colon were detected in seven. Such open-access, flexible sigmoidoscopy gave higher yield for colorectal polyps or cancers than open-access or hospital-initiation barium enema.(ABSTRACT TRUNCATED AT 250 WORDS)