Oxyphil parathyroid adenomas are rare and clinical features of patients with this entity are not well defined. We are presenting a case of primary hyperparathyroidism with marked elevation of parathyroid hormone (PTH) and near normal calcium levels, that underwent parathyroidectomy. Histopathology revealed an oxyphil adenoma which showed positivity for PTH on immunohistochemical staining. Post - operatively, there was a significant decline in both PTH and alkaline phosphatase levels. Benign oxyphil adenomas may mimic parathyroid carcinomas, both in terms of clinical features and tumour size; and they should be considered in the differential diagnosis of patients with primary hyperparathyroidism.