&NA;A retrospective review of 176 patients with adenocarcinoma of the colon who underwent total colonoscopy preoperatively demonstrated synchronous carcinomas in 3.4 percent and synchronous polyps in 55.1 percent. Full‐column barium enemas (68 patients) failed to identify cancer in 22 percent of patients and synchronous polyps in 58 percent of patients, a statistically significant (P<0.001) number of falsenegative examinations. Double‐contrast barium enemas (30 patients) failed to identify cancer in 27 percent of patients and synchronous polyps in 42 percent of patients, also a statistically significant (P<0.007) number of false‐negative examinations. Full column and air contrast barium enemas identified all index cancers with distant metastases. Air‐contrast barium enemas failed to identify 40 percent of “early” index cancers (confined to the bowel wall, negative nodes), and full‐column barium enemas failed to identify 32 percent. The incidence of synchronous carcinoma and polyps underscores the need for total colon evaluation when a primary carcinoma is detected. Because of the poor accuracy of barium studies, total colonoscopy is the method of choice for this evaluation.