Castleman's disease (giant lymph node hyperplasia) is an uncommon cause of neck mass. Its cause and pathogenesis are still unknown. Giant lymph node hyperplasia (GLH) usually presents as an asymptomatic solitary mass and can occur anywhere in the head and neck. Diagnostic test results are always inconclusive. Excision and histopathological evaluation are the only ways to make a definitive diagnosis. The disease is curable by surgical excision. A case of GLH presenting as a solitary neck mass in a 68-year-old man is reported. There has been no recurrence during about 7 months.