Summary: More than 90% of cancers are caused by environmental factors (e.g. tobacco smoke, unhealthy diet, excessive body weight, lack of physical activity, contact with toxic substances), and only some of them develop as a result of inherited predispositions. According to the World Health Organization, up to 50% of all deaths due to oncological diseases could be prevented by avoiding risk factors. The European Code Against Cancer was created in order to introduce the society to the principles of healthy lifestyle. Its current, fourth edition, presents information on carcinogens and how to avoid them in the form of 12 recommendations. In this paper, environmental risk factors for the development of cancers are discussed based on the European Code Against Cancer.