Cases of symptomatic Meckel's diverticulum treated surgically on an emergency basis during the last decade are reviewed. A series of 18 patients were divided into two groups depending on the presence or absence of ectopic tissue in the diverticulum. Group 1 consisted of five patients (28 percent) without ectopic tissue, and Group 2 consisted of 13 patients (72 percent) with ectopic tissue (8 gastric ectopia, 2 pancreatic ectopia, and 3 both gastric and pancreatic ectopia). Previous clinical records related to Meckel's diverticulum were found for 54 percent of the patients in Group 2 and for none of those in Group 1. The most common acute manifestations were intestinal occlusion (seven patients), digestive hemorrhage (five patients), and peritonitis (three patients). The postoperative course was 7 days in Group 1 and 15 days in Group 2 regardless of the surgical technique used. We conclude that the presence of ectopic tissue in patients with Meckel's diverticulum seems to be the main risk for occurrence of an acute nonmechanical complication. This complication appears more frequently and with more severity in young patients.