A 7-year and 11 month-old girl with cerebellar astrocytoma linked to familial ataxia-telangiectasia (AT) is presented. She was born as the 7th girl of a woman with aortic arch syndrome. Two elder sisters of the patient have ataxia telangiectasia. She had immunodeficiency, and cerebellar ataxia, but had no oculocutaneous telangiectasia. The risk of cancer developing in AT patients is about 1,200 times greater than that in age-matched controls. With regard to central nervous system tumours, seven primary tumours have been reported, such as 3 cases of medulloblastoma and 4 cases of glioma. Members of AT families who were under the age of 45 had a risk of dying of a malignant neoplasm five times greater than in the general population. However, there were no reports of glioma in AT families. In this case, it is suggested that IgA deficiency linked to familial AT may have contributed to the development of astrocytoma.