Telomerase expression strongly correlates with the grade of malignancy in glioma with inhibition illustrating a definite increase in chemosensitivity. This study was designed to investigate the effects of a green tea derivative, epigallocatechin-3-gallate (EGCG); together with either cisplatin or tamoxifen in glioma, and to investigate whether these effects are mediated through telomerase suppression. EGCG showed a significant cytotoxic effect on 1321N1 cells after 24 h and on U87-MG cells after 72 h (P < 0.001) without significantly affecting the normal astrocytes. Treatment with EGCG inhibited telomerase expression significantly (P < 0.01) and enhanced the effect of cisplatin and tamoxifen in both 1321N1 (P < 0.01) and U87-MG (P < 0.001) cells. EGCG, as a natural product has enormous potential to be an anti-cancer agent capable of enhancing tumour cell sensitivity to therapy.