We report a 79-year-old male patient presenting with progressive memory loss associated with anxiety and muscularpain. An extensive biochemical control revealed high serum calcium and parathormone levels, and normal thyroid hormones. Cognitive assessment prior to surgery was compatible with mild cognitive impairment, showing significant improvement two months after parathyroidectomy. Our case suggests that, although rare, primary hyperparathyroidism should be considered as a possible cause of cognitive decline in the elderly.