The high incidence of gliomas in Li-Fraumeni families and the high frequency of somatic p53 mutations in sporadic glial tumors have raised the possibility that germline p53 mutations could play an important role in familial aggregation of gliomas. In the present study, 18 families with two or more gliomas were screened for germline p53 mutation. The families were identified through questionnaires sent to 369 consecutive glioma patients operated at Tampere University Hospital during 1983-1994. In these families, a family history of cancer was verified through the Finnish Cancer Registry. Interestingly, the questionnaires reveled only 15 of 57 cancers (index gliomas excluded) retrieved through the Cancer Registry. None of the 18 families fufilled the criteria for classic Li-Fraumeni syndrome. Immunostaining analysis of p53 protein accumulation suggested that alterations of the p53 gene are as common in familial as in sporadic gliomas. Sequencing analysis of exons 4-10 of the p53 gene revealed no germline mutations in any of the 18 families. Thus, although occasional glioma families carrying germline p53 mutations have been identified in earlier studies, systematic evaluation of familial glioma patients suggests that the p53 gene is not a common susceptibility gene in case of familial gliomas. The p53 tumor suppressor gene seems to have a similar role in the tumorigenesis of most familial and sporadic gliomas.