Several nuclear receptors have recently been identified as mediators of endocrine disruption as well as steroid hormone receptors. The ubiquitous environmental contaminant tributyltin chloride (TBT) is a ligand for retinoid X receptor (RXR) in rock shell at the nanomolar level, and it acts as a ligand for both the RXR and the peroxisome proliferator-activated receptor γin the frog Xenopus laevis and in humans. TBT, which induces imposex in marine snails and promotes adipogenesis in X. laevis and in mice, is an example of an environmental endocrine disrupter that promotes adverse effects, from the snail to mammals, through common signaling. In addition, juvenile hormone agonists used as pesticides showed endocrine-disruptive effects on parthenogenic Daphnia magna, lowering rates of reproduction, and inducing 100% male offspring. In this article, we focus on commonality in signaling through nuclear receptors and newly found endocrine disruption in D. magna.