The most common types of malignant brain tumors in adults are brain metastasis and primary glioblastoma multiforme (GBM), both of which are highly lethal, with a median survival of less than a year. A critical challenge in treating brain tumors is the delivery of drugs to the central nervous system (CNS). The blood brain barrier (BBB), which has been shown to be partially disruptive even in the late stage of these brain tumors, prevents the access of therapeutic concentrations of systemic drugs to the tumor in brain parenchyma. Nanoparticle systems can represent optimal carriers for delivery of therapeutic agents. We will summarize various strategies used to improve nano-delivery of imaging contrast or therapeutic agents across BBB to brain tumors. Recent advances in molecular and cellular identifications of neurooncological biomarkers promise the advent of nanotechnology-based brain tumor-targeted detection and therapy. In this review, we will further discuss the current understanding of brain tumor biology and tumor type-specific genetic and epigenetic alterations, and advances in development of the novel nanoparticles for brain tumor imaging and therapy.