Using our novel estrogen-responsive transgenic (TG) zebra sh, we identi ed target tissues for environmental estrogens; these tissues have very high sensitivity even at environmentally rele- vant concentrations. Exposure of the TG sh to estrogenic endocrine-disrupting chemicals (EDCs) induced speci c expression of green uorescent protein (GFP) in a wide variety of tissues including the liver, heart, skeletal muscle, otic vesicle, forebrain, lateral line, and ganglions, most of which have not been established previously as targets for estrogens in sh. Furthermore, we found that dif- ferent EDCs induced GFP expression with di erent tissue response patterns and time trajectories, suggesting di erent potential health e ects.