All known cells continuously release nanoscale lipid membrane-enclosed packets. These packets, termed extracellular vesicles (EVs), bear the signature of their cells of origin. These vesicles can be detected in just about every type of biofluid tested, including blood, urine, and cerebrospinal fluid. The majority comes from normal cells, but disease cells also release them. There is a great interest in collecting and analyzing EVs in biofluids as diagnostics for a wide spectrum of central nervous system diseases. Here, we will review the state of central nervous system EV research in terms of molecular diagnostics and biomarkers.