AIM: In a retrospective study, the sensitivity of parathyroid scintigraphy and ultrasound was investigated in patients with primary hyperparathyroidism (HPT) with prior histories of surgery of the thyroid or parathyroid (unsuccessful or recidive). METHODS: Preoperative ultrasound and parathyroid scintigraphy were performed on 65 patients who had had successful surgery and on 12 who had had unsuccessful surgery. The scintigraphy was carried out using a combined double phase/double nuclide technique with 300-600 MBq 99mTc-sestamibi for parathyroid imaging and 80-100 MBq 99mTc-pertechnetate for thyroid imaging. RESULTS: The sensitivity of parathyroid scintigraphy was 86% in patients with normal thyroid glands, 77% in those with recurrent goiter, and 62% in those with recurrent or persistent HPT. The ultrasound sensitivity was 86%, 50%, and 57% respectively. CONCLUSION: The sensitivity of parathyroid scintigraphy and ultrasound decreases considerably after surgery. That of parathyroid scintigraphy lay significantly below results published to date. However, parathyroid scintigraphy should be performed precisely in these cases, because the number of alternative parathyroid imaging methods aside from ultrasound are limited.