Xenobiotic substance released in the environment is a concern among the public at large. The example of this xenobiotic release into the environment is xenoestrogens. Xenoestrogens have the capability to bind to the estrogen receptors in the body even at low affinity. Food, pesticides and contraceptive pills are known sources of xenoestrogens. In this study, acute toxicity test was conducted to evaluate toxicity of synthetic estrogen such as estradiol to the embryo-larvae of zebrafish model. Morphological changes in the embryo-larvae of zebrafish were also observed. The parameters that were evaluated in acute toxicity study were half lethal concentration (LC50) and few apical endpoints such as coagulation of embryos, development of pericardial edema, and eyes size. Toxicity effect of the compound was evaluated in term of behavior activity of the larvae. Results showed that certain concentration of estradiol caused toxic effects to the embryo-larvae of the zebrafish (p