The annual incidence of the acromegaly is three cases per million, and that of the familial acromegaly is even far rarer. The number of familial acromegaly reported in the medical literature of all the world is fewer than 10 cases per year, and up till now none of such a patient has been reported in China. All the three cases of familial acromegaly reported here were from the same family, and showed typical clinical manifestations. They presented the history of acral enlargement, headache, amenorrhoea, elevated serum GH level, enlargement and erosion of pituitary fossa in X-ray and CT scan, and characteristic immunohistochemical findings of GH-secreting pituitary adenoma. All of them underwent successful transsphynoidal total removal of the pituitary adenoma, and recovered well by clinical, endocrine, and pathological criteria. An extended family tree of 65 members excluded consanguinous marriage and suggested that the mode of inheritance was irregular autosomal dominant.