Mothers against decapentaplegic homologue 4 (Smad4) is associated with several human cancers. However, the exact mechanism of Smad4 in human glioma is still unknown. In this study, we constructed a recombinant adenovirus encoding Smad4 and transduced it into glioma cells. The results demonstrated that the overexpression of Smad4 not only suppressed glioma cell proliferation but also increased cell apoptosis by promoting cell cycle arrest at G1 phase. Furthermore, an adenovirus encoding Smad4 suppressed tumor formation in nude mice. These findings clearly demonstrate that Smad4 plays an important role in human glioma development by regulating cell proliferation. Moreover, Smad4 may represent a potential therapeutic target in glioma. HIGHLIGHTS