Glioblastoma multiforme (GBM) is the deadliest brain tumor with an approximate 14 month survival rate after diagnosis and treatment. Temozolomide (TMZ), the chemotherapeutic drug of choice for GBM, is an alkylating agent that causes DNA damage. TMZ treatment results in the induction of apoptosis in GBM cells, however, it induces autophagy and consequently chemoresistance. Statins are mevalonate (MEV) cascade inhibitors with beneficial effects on the enhancement of the survival rate of patients with different types of cancer. Here, we determined the effect of simvastatin (Simva), a blood brain barrier permeable statin, on the sensitization of GBM cells to TMZ induced apoptosis through inhibition of autophagy flux. We pretreated two GMB cell lines, U251 and U87 cells, with low doses of Simva (1 and 2.5 M, respectively) with or without different intermediates of the mevalonate cascade and then treated cells with TMZ (100 M) for 48-96 hrs. A signficiantly reduced viability and increased in the population of apoptotic dead cells were observed in GBM cells treated with the Simva-TMZ compared to cells treated with TMZ alone. Addition of MEV, Farnesyl pyrophosphate, Geranylgeranyl pyrophosphate and cholesterol did not attenuate these effects significantly. Sima-TMZ treatment did not alter the total cholesterol pool in U87 and U251 cells compared to controls. Western blot analysis, immunocytochemistry and transmission electron microscopy revealed that Simva-TMZ inhibited autophagic flux. Overall, the results suggest that sensitization of GBM cells to TMZ-induced apoptosis by Simva is independent on the cholesterol biosynthetic pathway but may involve inhibition of autophagy.