Gene transfer to photoreceptor cells may provide a means for arresting the retinal degeneration that is characteristic of many inherited causes of blindness, including retinitis pigmentosa (RP). However, transduction of photoreceptors has to date been inefficient, and further limited by toxicity and immune responses directed against vector-specific proteins. An alternative vector system based on adeno-associated virus (AAV) may obviate these problems, and may be useful for transduction of neuronal cells. In this study we have demonstrated successful transduction of all layers of the neuroretina as well as the retinal pigment epithelium (RPE) following subretinal injection of recombinant AAV particles encoding lac Z. Furthermore, the efficiency of transduction of photoreceptors is significantly higher than that achieved with an equivalent adenoviral vector. This is the first report showing that AAV is capable of transducing photoreceptor cells and supports the use of this vector system for gene therapy of retinal diseases such as RP.