We sought to investigate predictors of early development of postoperative hypocalcemia in secondary hyperparathyroidism. Thirty-six hemodialysis patients (21 men, 15 women; mean age, 39.6 +/- 13.2 years; mean hemodialysis duration, 77.9 +/- 47.1 months) underwent parathyroidectomy. We recorded preoperative adjusted serum calcium (Ca(+2)), phosphate, alkaline phosphatase, intact parathyroid hormone, and hemoglobin levels; mean systolic and diastolic blood pressure levels; parathyroid ultrasonography and scintigraphic data; and number and weight of the resected adenomas. Patients were divided into two groups based on Ca(+2) levels within 24 hours of parathyroidectomy: the hypocalcemia group (serum Ca(+2) levels < or = 8 mg/dL; n = 26 patients) and the normocalcemia group (>8 mg/dL; n = 10 patients). A total parathyroidectomy with autotransplant was performed in 23 patients and a subtotal parathyroidectomy in 13 patients. Age (36.0 +/- 9.7 vs 49.2 +/- 16.6 years; P = .006); levels of preoperative serum Ca(+2) (9.6 +/- 0.7 vs 10.4 +/- 1.1 mg/dL; P = .01), alkaline phosphatase (346.7 +/- 354.7 vs 653.3 +/- 553.7 mg/dL; P = .05), and hemoglobin (10.5 +/- 1.4 vs 12.3 +/- 2.5 g/dL; P = .009); and number (2.0 +/- 1.3 vs 2.9 +/- 0.9; P = .04) and weight (1.9 +/- 2.1 vs 3.2 +/- 1.7; P = .01) of excised parathyroid adenomas were significantly lower among the hypocalcemia than the normocalcemia group. Among hemodialysis patients with secondary hyperparathyroidism, age, levels of preoperative serum Ca(+2) and alkaline phosphatase, and number and weight of adenomas were associated with early development of postoperative hypocalcemia.