One hundred and thirty-six (136) malignant glioma patients receiving temozolomide will be accrued in this open labeled phase II randomized single institution trial of Aprepitant in combination with Ondansetron vs. Ondansetron alone for the prevention of acute and delayed CINV. Sixty-eight (68) patients will be randomized to each arm of the study. Patient randomization will be stratified by grade (I/II vs. III/IV) and the number of prior progressions (0/1 versus 2). Within each of the 4 strata defined by these factors, a permuted block randomization scheme will be used to assign patients to receive either Ondansetron with or without Aprepitant.