Two cases of perforated duodenal diverticulum, treated at the surgical Emergency Service of the Hospital das Clínicas of the University of São Paulo Medical School are reported. Although duodenal diverticula are frequent their perforation in is a rare and dougerous complication. Diagnosis and surgical treatment are discussed. We believe that excision, primary suture with an omental patch and drainage are procedures of choice for the treatment of this complication.