Brain diseases are notoriously difficult to treat due to the presence of the blood-brain barrier (BBB). Here, we review the development of focused ultrasound (FUS) as a noninvasive method for BBB disruption, aiding in drug delivery to the brain. FUS can be applied through the skull to a targeted region in the brain. When combined with microbubbles, FUS causes localized and reversible disruption of the BBB. The cellular mechanisms of BBB disruption are presented. Several therapeutic agents have been delivered to the brain resulting in significant improvements in pathology in models of glioblastoma and Alzheimer's disease. The requirements for clinical translation of FUS will be discussed.