Quality of Recovery-15 (QoR-15) has received attention as a postoperative patient-reported outcome measure. Preoperative nutritional status has negative effects on postoperative outcomes; however, these associations have not yet been investigated. We included inpatients aged ≥ 65 years who underwent elective abdominal cancer surgery under general anaesthesia between 1 June 2021 and 7 April 2022 at our hospital. Preoperative nutritional status was assessed using the Mini Nutritional Assessment Short-Form (MNA-SF), and patients with an MNA-SF score ≤ 11 were categorised into the poor nutritional group. The outcomes in this study were the QoR-15 scores at 2 d, 4 d and 7 d after surgery, which were compared between groups by unpaired t test. Multiple regression analysis was applied to assess the effects of poor preoperative nutritional status on the QoR-15 score on postoperative day 2 (POD 2). Of the 230 included patients, 33·9 % (78/230) were categorised into the poor nutritional status group. The mean QoR-15 value was significantly lower in the poor nutritional group than in the normal nutritional group at all postoperative time points (POD 2:117 v. 99, P = 0·002; POD 4:124 v. 113, P < 0·001; POD 7:133 v. 115, P < 0·001). Multiple analyses showed that poor preoperative nutritional status was associated with the QoR-15 score on POD 2 (adjusted partial regression coefficient, −7·8; 95 % CI −14·9, −0·72). We conclude that patients with a poor preoperative nutritional status were more likely to have a lower QoR-15 score after abdominal cancer surgery.