In the postgenomic era the elucidation of the physiological function of genes has become the rate-limiting step in the quest to understand the development and function of living organisms. Gene functions cannot be determined by high-throughput methods but require analysis in the context of the entire organism. This is particularly true in the developing vertebrate nervous system. Because of its easy accessibility in the egg, the chicken embryo has been the model of choice for developmental in vivo studies. However, its usefulness has been hampered by a lack of methods for genetic manipulation. Here we describe an approach that could compensate for this disadvantage. By combining gene silencing by dsRNA (through RNA interference, RNAi) with in ovo electroporation, we developed an efficient method to induce loss of gene function in vivo during the development of the chicken CNS. This method opens new possibilities for studying gene function not only by gain-of-function but also by loss-of-function approaches and therefore represents a new tool for functional genomics.