Aim. Novel non-nucleoside inhibitors of MGMT (O⁶-methylguanine-DNA methyltransferase) have shown high efficacy and low level of cytotoxicity in human cancer cells HEp-2. But it is important to investigate the impact of new inhibitors in other human cancer cells, especially, those which have different levels of MGMT expression. This study was performed using two glioma cell lines: T98G with a high level of MGMT expression and U251MG with a methylated promoter in the MGMT gene. Methods. Western-blot analysis of the level of MGMT. The autophagy level and number of alive and dead cells were measured with fluorescence microscopy and fluorescence spectrophotometry after Monodansylcadaverine dying for autophagosomes and dying by Live-Dead Imaging Cell Kit respectively. Results. The new inhibitors significantly reduce MGMT level, but this effect could be observed only after 24-hour treatment. Longer treatment has a weaker inhibiting effect compared with standard inhibitor O6-benzylguanine. The combined treatment by the inhibitors and nitrosoguanidine induces a high autophagy level in T98G cells, whereas in U251MG cells a low level of autophagy was observed. The analyzed inhibitors do not elevate the level of dead cells in both cell lines. However, the combined treatment leads to a high death rate only in T98G cells. Conclusions. The analyzed compounds have inhibiting activity against MGMT in glioma cells. The inhibitors don’t affect glioma cells’ survival and autophagy level however make them more sensitive to an alkylating agent.