We report the case of parathyroid adenoma incidentally discovered during a total thyroidectomy. The patient showed no clinical or biochemical signs that led us to suspect a hyperparathyroidism condition before the operation. But a macroscopically enlarged parathyroid was discovered during the dissection and it was removed. The patients had a single adenoma confirmed by histological analysis. No permanent hypoparathyroidism or recurrent hyperparathyroidism was observed. We recommend that any enlarged parathyroid discovered during neck surgery should thus be removed to avoid the risks of future surgical procedures due to successive both of clinical hyperparathyroidism.