Glioma describes a tumor that starts within the spinal cord or brain, and originates from glial cells; gliomas are the most commonly-found malignant brain tumors in Indonesia. Until now, there was no specific molecular biomarker used to distinguish gliomas based on tumor grade. TGF-β1 plays a key role in maintaining tissue homeostasis and cancer progression. Because of this, TGF-β1 has potential as a biomarker for differentiating between low-and high-grade gliomas. Samples were collected from patients with gliomas at the Cipto Mangunkusumo Hospital, Indonesia. The samples were categorized as low- (grades 1 and 2) or high- (grades 3 or 4) grade gliomas through histopathologic examination and based on the guidelines set forth by the World Health Organization. Relative mRNA expression of TGF-β1 was quantified through real-time RT-PCR with 18sRNA as the housekeeping gene. There were 27 glioma patient consisting of 17 low-grade glioma tissues and 10 high-grade glioma and 2 normal brain tissues as controls. There were 13 male and 14 female patients, with 63% <40 years old. There was decreased relative expression of TGF-β1 in high-grade, compared to low-grade, gliomas. However, this difference was not statistically significant. The role of TGF-β1 as a definite biomarker was not proven in this study; therefore, more research should be conducted to elaborate the role of TGF-β1 as a biomarker. © 2018 Institute of Physics Publishing. All rights reserved.