['Perforated diverticulitis (PD) remains a serious acute abdominal condition. The aim of this study was to evaluate indications for emergency surgery in patients ≥80\xa0years of age with PD.', 'Twenty patients ≥80\xa0years of age and 28 younger patients who underwent emergency surgery for PD from January 2002 to December 2011 were studied. The demographics and postoperative outcomes were compared.', 'The preoperative characteristics, mortality rate, and postoperative complications were similar between these two groups. All seven patients ≥80\xa0years of age with an American Society of Anesthesiologists (ASA) score of 2 survived after surgery. All five patients with a Mannheim peritonitis index (MPI) score of ≥26 in the elderly group died after surgery. There were significant associations between the mortality, the MPI and ASA score in patients ≥80\xa0years of age.'] Do indications for emergency surgery for perforated diverticulitis in elderly Japanese patients ≥80 years of age?