ABSTRACT Brown tumor also known as osteitis fibrosa cystica generalisata or Von Recklinghausen’s disease of bone, is a metabolic bone disease that develops in primary, secondary or tertiary hyperparathyroidism. Brown tumors can occur in any location but are most common in the ribs, clavicle and pelvis. The reported prevalence of brown tumors is 3% in primary hyperparathyroidism and can occur in mandible very rarely [1]. We describe an unusual case of primary hyperparathyroidism in a 30-year-old female patient presenting with mandibular brown tumor as the first clinical manifestation. It should be differentiated from other true giant cell tumors of bone. Keywords: Brown tumour, primary hyperparathyroidism, parathyroid adenoma, mandible.