INTRODUCTIONIn the last two decades, the small tropical freshwater-dwelling zebrafish has emerged as a popular model for developmental biologists. The exceptional optical accessibility of zebrafish embryos coupled with the ability to use genetic tools to indelibly tag cells have been exploited to watch developmental events as they unfold. Moreover, because zebrafish are vertebrates, the knowledge gained through such studies is broadly applicable. This protocol describes the procedure for imaging zebrafish development. Once zebrafish cells have been labeled with fluorescent molecules or stained with fluorescent dye, the developmental processes of interest can be analyzed using a wide variety of live imaging techniques, such as wide-field microscopy, confocal microscopy, or multiphoton microscopy.