Through a comprehensive review of the Mayo Clinic experience with patients who had Meckel diverticulum, we sought to determine which diverticula should be removed when discovered incidentally during abdominal surgery. Meckel diverticula occur so infrequently that most articles have reported either small series or isolated cases. From these limited series, various conclusions have been reported without clearly indicating which incidental diverticula should be removed. Medical records were reviewed of 1476 patients found to have a Meckel diverticulum during surgery from 1950 to 2002. Preoperative diagnosis; age; sex; date of surgery; and intraoperative, macroscopic, and microscopic findings from operative and pathology reports were recorded. Logistic regression analysis was used to determine which clinical or histologic features were associated with symptomatic Meckel diverticulum. The features analyzed were age; sex; length, base width, and ratio of length to base width of the diverticulum; and the presence of ectopic tissue or abnormal tissue (inflammation or enteroliths). Among the 1476 patients, 16% of the Meckel diverticula were symptomatic. The most common clinical presentation in adults was bleeding; in children, obstruction. Among patients with a symptomatic Meckel diverticulum, the male-female ratio was approximately 3:1. Clinical or histologic features most commonly associated with symptomatic Meckel diverticula were patient age younger than 50 years (odds ratio [OR], 3.5; 95% confidence interval [CI], 2.6-4.8; P < 0.001), male sex (OR, 1.8; 95% CI, 1.3-2.4; P < 0.001); diverticulum length greater than 2 cm (OR, 2.2; 95% CI, 1.1-4.4; P = 0.02), and the presence of histologically abnormal tissue (OR, 13.9; 95% CI, 9.9-19.6; P < 0.001). After analyzing our data, we neither support nor reject the recommendation that all Meckel diverticula found incidentally should be removed, although the procedure today has little risk. If a selective approach is taken, we recommend removing all incidental Meckel diverticula that have any of the 4 features most commonly associated with symptomatic Meckel diverticulum.