We analyzed the sensitivity of the barium enema examination in 128 patients with 191 endoscopically proven colonic polyps and 12 carcinomas, relative to patient age, indications, and the type of examination used. Seventy-seven patients (60%) had rectal bleeding, and 51 (40%) patients with 87 lesions, including six carcinomas, did not. Overall roentgenographic sensitivity was 88%, with a 93% detection rate in patients less than 70 years old as compared to 76% for older patients. Sensitivity of single- and double-contrast barium enema examination was 82% and 91%, respectively. There were similar detection rates for lesions 1 cm or more in size (91% vs 95% for single- and double-contrast examinations, respectively), but double-contrast examination was slightly better at detecting smaller polyps (88%, vs 70% for single-contrast examination). Compared to colonoscopy, which has an average reported false-negative rate of 12% in detecting neoplasms, the barium enema is similarly reliable, less costly, and safer.