AltTox.org is a website dedicated to advancing non-animal methods of toxicity testing, both to better protect the health of humans, animals, and the environment and to reduce the numbers and suffering of animals used in current toxicology assessments. The website is designed to encourage the exchange of technical and policy information on in vitro and in silico methods for all types of toxicity tests. The target audience includes stakeholders in industry, government, academia, and nongovernmental organizations.