BACKGROUND : Dementia often adversely affects postoperative outcomes in surgical patients. This study evaluated postoperative outcomes among elderly patients with and without dementia undergoing early cholecystectomy for acute cholecystitis (AC). METHODS : A total of 182 patients over 85 years of age who were diagnosed with AC and treated from January 2005 to March 2018 were reviewed retrospectively; 59 patients who underwent early cholecystectomy were enrolled. The complication rates, length of postoperative hospital stay, and rates of routine discharge (i.e., returning to their preoperative living location) were compared between two groups of patients with and without dementia. RESULTS : The overall complication rate after early cholecystectomy for AC in 59 patients was 11.9%, and there was no mortality in this series. The median postoperative hospital stay was 9.0 days, and the routine discharge rate was 89.8%. Of the 59 patients, 22 patients (37.3%) had a history of dementia. Complication rates were comparable between the groups, despite the rate of delirium development being significantly higher in the dementia group. The median length of postoperative hospital stay and routine discharge rates did not significantly differ between groups. CONCLUSIONS : Early cholecystectomy for patients with AC over 85 years of age was performed safely, and elderly patients with dementia had similar postoperative outcomes as compared with patients without dementia.