Glioblastoma is one of the most aggressive tumors in mankind with 50% of patients dying within the 1st year of diagnosis, and being refractory to conventional therapies. The aim of our work has been to analyse the expression of the HMGA1 proteins in human astrocytomas and glioblastomas in order to verify whether the detection of these proteins might be of some help in the diagnosis of these neoplasias. Here we report the analysis of 27 cases, including 12 astrocytomas and 15 glioblastomas, for HMGA1 expression. All the neoplastic samples showed positive staining even though the number of positive cells and the staining intensity was higher in glioblastomas compared to astrocytomas. Conversely, HMGA1 proteins were not detected in normal brain. Accordingly, expression of the hmga1 gene, analysed by RT-PCR, was higher in glioblastomas than in astrocytomas.