[Objective] To explore the risk factors of postoperative fever in primary aldosteronism (PA) patients. [Methods] Clinical data of 116 PA patients undergoing adrenalectomy in Peking University People's Hospital during Jan.2018 and Jul.2021 were retrospectively analyzed.Based on postoperative body temperature, the patients were divided into fever group (body temperature ≥38.0 ℃, n=41) and non-fever group (body temperature <38.0 ℃, n=75). Clinical features were analyzed between the two groups.The fever group was subdivided into low fever group (38.0 ℃≤body temperature <38.5 ℃, n=19) and high fever group (body temperature ≥38.5 ℃, n=22). The clinical data of the subgroups were compared. [Results] The incidence of postoperative fever was 35.3%.Logistic regression analysis showed that lower lowest potassium on records (OR=0.419, 95%CI: 0.196-0.894, P=0.025), lower high-density lipoprotein cholesterol (HDL-C) (OR=0.112, 95%CI: 0.018-0.687, P=0.018), and postoperative adrenal insufficiency (OR=4.158, 95%CI: 1.731-9.989, P=0.001) were independent risk factors for postoperative fever.There was no difference between the high and low fever groups.After surgery, infection occurred in 1 patient, adrenal insufficiency in 40 (34.5%) patients, but long-term follow-up indicated that no patients needed lifelong glucocorticoid replacement. [Conclusion] Fever is a common postoperative complication in PA patients, most likely due to transient adrenal insufficiency.Glucocorticoid supplementation should be administered appropriately and timely based on laboratory tests and clinical manifestations.Evaluation of adrenal function is highly recommended for patients undergoing adrenalectomy.