Transgenes can be introduced into the cells of organotypic slice cultures using different delivery methods, such as biolistic transfection, electroporation, and viral vector-based transduction. These methods produce different patterns of transgene expression. Local injection of recombinant adeno-associated virus (rAAV) produces a small cluster of transgene-expressing neurons around the injection site. Expression in individual cells varies with the distance from the injection site, indicating that many neurons take up several rAAV particles. The serotype and promoter also play a role in transgene expression. Here, we present a protocol for the transduction of previously prepared hippocampal slice cultures with rAVV.