We assessed the clinical significance and risk factors of incidental parathyroidectomy during total thyroidectomy with or without central neck dissection or subtotal thyroidectomy.Retrospective analysis of clinical and pathological features of 548 consecutive thyroidectomy cases was compared by grouping into inadvertent resection (IR, n = 86) with IR of parathyroid glands, non-IR (n = 462) without, and then into postoperative hypoparathyroidism (PH, n = 140) with PH and non-PH (n = 408) without.Two hundred ninety-eight patients had total thyroidectomy and 250 had subtotal thyroidectomy. IR had higher malignant disease (P < .001), total thyroidectomy (P = .016), T3 and T4 classification (P = .005), central neck dissection (P < .001), recurrent laryngeal nerve palsy (P = .003), postoperative transient hypoparathyroidism (P < .001), duration of disease prior to thyroidectomy (P < .001), and weight of excised thyroid tissue (P < .001) than non-IR.Preoperative diagnosis of malignant disease, duration of disease prior to thyroidectomy, and central neck dissection were independent risk factors for incidental parathyroidectomy. Preoperative diagnosis of malignant disease, central neck dissection, duration of disease prior to thyroidectomy, weight of excised thyroid tissue, and incidental parathyroidectomy were correlated with PH.