Recombinant adeno-associated virus (AAV)-based vectors expressing therapeutic gene products have shown great potential for human gene therapy. One major challenge for translation of promising research to clinical development is the manufacture of sufficient quantities of AAV vectors that meet stringent standards for purity, potency, and safety required for human parenteral administration. Several methods have been developed to generate recombinant AAV in cell culture, each offering distinct advantages. Transient transfection-based methods for vector production are reviewed here, with a focus on specific considerations for development of AAV vectors as clinical products.