Amphibians as animal models have long been employed as indicators of environmental quality and to detect toxicity risks of environmental pollutants. The increased attention to the use of non-traditional species of amphibians in ecotoxicology and genotoxicology research lies in their ability not only to reveal the toxic and genotoxic effects of many potential environmental xenobiotics, but also to help researchers understand the behaviour of real ecosystems. This chapter presents an overview of selected research that has led to the use of the common tree frog Hypsiboas pulchellus as a reliable and valid model in in vivo and in situ studies of aquatic pollution.