Recent advances in understanding the biology of osteoarthritis have allowed the design of novel therapeutic strategies based on biologic principals. Gene therapy is one such strategy. The underlying concept is to deliver to patients with OA genes that have products with antiarthritic properties. This results in the endogenous production of these products in a sustained and ultimately regulated fashion, thereby obviating the problems that exist with traditional methods of drug delivery. Synovium and articular cartilage are two attractive sites for the delivery of anti-OA genes. Preliminary experimental data support the use of these concepts.