The ECT2 (epithelial cell transforming sequence 2) proto-oncogene encodes a guanine nucleotide exchange factor for Rho GTPases, and regulates cytokinesis. ECT2 plays a critical role in Rho activation during cytokinesis, and thus may play a role in the pathogenesis of glioma. In this study, we investigated relationships between ECT2 expression, tumor histology, and prognosis in glioma patients. ECT2 mRNA expression was examined using quantitative real-time PCR, while its protein expression was examined by immunohistochemistry of 54 glioma tissue samples. Expressions of ECT2 mRNA and protein were markedly increased in high-grade gliomas compared to low-grade gliomas. Patients in whom expression of ECT2 mRNA and protein in tumor tissues was the lowest survived longer than patients who had higher expression. In vitro, ECT2 siRNA inhibited glioma cell proliferation and invasion. These data suggest that increased expression of ECT2 contribute to promotion of tumor invasiveness and progression, implying that evaluation of ECT2 expression is a prognostic marker for glioma patients.