Recombinant adeno-associated virus (rAAV) is a promising vector for somatic gene therapy due to the ability to transduce terminally-differentiated and non-dividing cells, the lack of any apparent pathogenicity, a low immunogenicity, a relatively high stability of transgene expression, and the potential for targeted integration. Improved methods of rAAV packaging allow the generation of concentrated and highly purified rAAV for clinical trials. Preclinical studies with rAAV are currently in progress for the treatment of a variety of inherited monogenic defects, but also for acquired diseases like HIV infection and cancer. Because of the broad host range of wild type AAV, rAAV is able to transduce a variety of human tissues, preferentially those of epitheloid origin, with high efficiency and therefore may be used for various clinical applications. Whilst several issues including safety, tissue tropism and methods to achieve site-specific integration need further improvement, rAAV certainly has a sufficient number of advantages to be seriously considered as a gene therapy vector.