The objective of this study was to evaluate the effect of Enhanced Recovery After Surgery plus preoperative antifrailty (PAFERAS) on surgical outcomes of frail patients who underwent long-segment surgery for adult spinal deformity (ASD).This is a retrospective study using a prospectively collected ASD database. Patients who underwent open long-segment fusion surgery (≥ 5 levels) for ASD between January 2017 and March 2024 were classified as nonfrail (NF; 5-factor modified frailty index [mFI-5] score = 0), prefrail (PF; mFI-5 score = 1), or frail (mFI-5 score ≥ 2) based on their physical activity and comorbidities. For frail patients, the antifrailty interventions of the PAFERAS program focused on preoperative exercise and nutritional optimization. NF/PF patients of the PAFERAS group received preoperative dietary counseling, nutritional education, and standardized rehabilitation advice. Meanwhile, frail patients were divided into non-PAFERAS (before January 2019) and PAFERAS (after January 2019) groups based on whether they received PAFERAS care or not. Frail patients with antifrailty (AF group) were compared with PF patients, NF patients, and frail patients in the non-PAFERAS group. AF patients were propensity score matched 1:1 to the NF, PF, and non-PAFERAS groups patients based on age, pelvic incidence minus lumbar lordosis, and intraoperative estimated blood loss.A total of 286 patients from the PAFERAS group (31.8% in the NF group, 46.9% in the PF group, and 21.3% in the AF group) and 142 patients from the non-PAFERAS group were included in the final analysis. The 1st day of assisted walking occurred, on average, 1 day earlier in the AF group than in frail patients from the non-PAFERAS group (3.52 vs 2.54 days, p = 0.016). The postoperative length of hospital stay (LOS) for frail patients significantly decreased from 14.29 days before PAFERAS to 10.64 days after PAFERAS (p = 0.011). No significant differences were observed between the matched AF and NF/PF groups in the 1st day of assisted walking and the 1st day of bowel movement. There were no differences between the AF and NF/PF groups in postoperative LOS, nonhome discharge rate, rates of severe complications, and rates of minor complications.The PAFERAS protocol significantly improves the return of physiological function and the LOS for frail patients undergoing ASD surgery. After implementing preoperative exercise and nutritional optimization for frail patients, the recovery process of physiological function and LOS in patients with frailty were similar to those in NF or PF patients.