Despite the increasing prevalence of spinal surgery in super-elderly (SE) patients, the outcomes and complication rates have not been fully elucidated. The purpose of this study was to compare the outcomes and complications of lumbar spinal fusion for degenerative lumbar spinal stenosis (DLSS) in SE patients aged 80 years and over with those in patients aged 65 years and over, and under 80 years.This study analyzed 160 patients who underwent spinal fusion for DLSS between January 2011 and November 2019. Thirty patients in the SE group (group SE, ≥80 years) and 130 patients in the elderly group (group E, ≥65 years and <80 years) were enrolled. The performance status was evaluated by preoperative American society of anesthesiologists (ASA) score. Visual analog scales for back pain (VAS-BP) and leg pain (VAS-LP), and Korean Oswestry disability index (K-ODI) were used to assess clinical outcomes preoperatively and 1 year postoperatively. Percent changes of VAS-BP, VAS-LP and K-ODI were also analyzed. Fusion rates were evaluated by computed tomography 6 months and 1 year postoperatively. Furthermore, bone mineral density, operative time, estimated blood loss, blood transfusion, hospital days, hospitalization in intensive care unit and postoperative complications were compared.The average age of group SE was 82.0 years and that of group E was 71.6 years. There were no differences in preoperative ASA score, preoperative or postoperative VAS BP and VAS-LP, bone mineral density, operative time, estimated blood loss, blood transfusion, hospital days, hospitalization in intensive care unit and fusion rates between the groups. Preoperative and postoperative K-ODI were higher in group SE than group E (all P < .05). However, percent changes of VAS-BP, VAS-LP and K-ODI showed no significant differences. Overall early and late complications were not significantly different between the groups; however postoperative delirium was more common in group SE than group E (P = .027). SE status was the only risk factor for postoperative delirium with odds ratio of 3.4 (P = .018).Spinal fusion surgery is considerable treatment to improve the quality of life of SE patients with DLSS, however careful perioperative management is needed to prevent postoperative delirium.