Abstract Chickens and their embryos provide a valuable research model for the study of developmental biology and human diseases. However, their application has been greatly limited due to the lack of tools to genetically modify chickens and other avian species. Recently, we have developed methods for the derivation of germline competent embryonic stem cells (ESCs) from chickens. The availability of germline competent chicken ESCs opens up a new avenue for producing genetically engineered chickens. In this project, we propose to establish an ESC-based platform for the efficient generation of chicken germline chimeras (Aim 1). We will also optimize methods for the generation of primordial germ cells (PGCs) from chicken ESCs. These chicken ESC-derived PGCs will be used to produce genetically modified chickens (Aim 2). In Aim 3, by taking the advantage of the chicken ESC culture condition we have established, we will develop methods for the generation of induced pluripotent stem cells (iPSCs) from chicken embryonic fibroblasts. Successful completion of these three aims will provide the avian research community with a powerful genetic toolkit for the production of transgenic and gene-targeted avian species and for the conservation of endangered avian species.