Naturally occurring compounds (e.g., lipids and proteins) can serve as constituents for carrier production; biological entities per se may also function as ready-made carriers for systemic delivery. Examples of these entities include bacteria, viruses, erythrocyte ghosts, and exosomes. While many of these entities have been extensively reviewed in the literature on therapeutics delivery, comparatively little discussion has focussed on exosomes, a subset of extracellular vesicles released by all types of cells which are involved in local and systemic intercellular communication. In fact, exosomes carry a wide range of cargos (including nucleic acids, proteins, and lipids derived from their cell of origin) to recipient cells. This cargo-carrying systemic delivery system has already been exploited in the literature to transport therapeutics to target cells. In this chapter, we will provide an overview of the function, activity, and mechanisms of exosomes, methods for exosome isolation and cargo loading, and strategies for specific targeting of cells. The considerable potential for exosomes as a delivery method for therapeutics in disease will also be highlighted.