Investigation of the adeno-associated virus (AAV) life cycle has enabled the establishment of methodology and identification of critical cis-acting sequences required for recombinant AAV production. Vectors derived from the defective human parvovirus (AAV) have been used for successful gene transfer and expression in many diverse mammalian cell types, such as erythroid, airway epithelium, and neuronal cells. One of the crucial steps in the continued case of AAV as a vector is the development of packaging systems that will allow efficient encapsidation of foreign genes into AAV virions. For this reason, the focus of this article will be generation of recombinant AAV vectors.