A promising approach for the therapeutic treatment of brain tumors utilizes replication-competent, neuroattenuated herpes simplex virus-1 (HSV-1) mutants. This approach requires mutation of HSV-1 to eliminate killing of normal, non-dividing cells of the brain (e. g. , neurons). The present invention discloses methods for killing malignant brain tumor cells in vivo entails providing replication competent herpes simplex virus vectors to tumor cells. A replication competent herpes simplex virus vector, with defective expression of the gamma 34. 5 gene and the uracil DNA glycosylase (UNG) gene, specifically destroys tumor cells, is hypersensitive to anti-viral agents, and is not neurovirulent.