Treatment for primary hyperparathyroidism necessitates complete excision of involved parathyroid tissue. Simultaneous thyroidectomy may also be required in order to optimise operative access and/or where suspicion of synchronous abnormal thyroid pathology exists. We sought to determine how often simultaneous removal of thyroid tissue was required during parathyroidectomy and the nature of any associated pathology. Radiology reports were also reviewed to determine how often confirmed thyroid pathology from histological specimens, benign or malignant, had been identified pre-operatively. A retrospective chart review of 135 parathyroidectomy procedures performed between 2003 and 2013 was performed. Of 135 parathyroidectomy procedures, 39 patients (29%) underwent simultaneous partial thyroidectomy of which 36 (27% of total parathyroidectomies) had dual pathology confirmed. Specifically, malignant lesions were identified in 14% (n = 5), Graves' disease 3% (n = 1), thyroiditis 17% (n = 6), multinodular goitre 50% (n = 18), unilateral nodule 6% (n = 2), hyperplasia 8% (n = 3) and intra-thyroid adenoma 3% (n = 1). Reference to these thyroid lesions was made in only 47% of preoperative radiology reports. In conclusion, synchronous thyroid surgery was required in 29% of all parathyroidectomy procedures performed for treatment of primary hyperparathyroidism with malignant thyroid lesions incidentally detected in 14% of cases. Less than half of all confirmed concomitant thyroid pathology had been referred to or recognised on pre-operative radiology studies. These findings highlight the importance of considering the potential need to perform thyroid surgery during parathyroidectomy and obtaining appropriate informed consent.