OBJECTIVE: This study aimed to assess the effectiveness of intraoperative parathyroid hormone (PTH) measurements from bilateral internal jugular veins (BIJVs) in determining parathyroid gland laterality during surgery for primary hyperparathyroidism (PHPT). STUDY DESIGN: Prospective cohort study. SETTING: Single tertiary care center, February 2021 to February 2023. METHODS: All patients underwent intraoperative BIJV PTH measurements during parathyroidectomy. Preoperative localization of abnormal parathyroid glands was performed using cervical ultrasound (USG) and sestamibi scans (MIBI). Receiver operating characteristic (ROC) analysis was performed to determine the best performance (sensitivity and specificity) for predicting parathyroid gland laterality. RESULTS: A total of 124 patients underwent surgery during the study. PTH measurements from BIJV successfully confirmed the laterality of parathyroid adenomas in 102 cases (82.3%, CONCLUSION: Intraoperative BIJV PTH measurement is a valuable adjunct in parathyroidectomy, improving localization and enhancing surgical outcomes in PHPT patients.