Active packaging is a new generation of packaging that, unlike traditional packaging, allows the preservation of food, not only contains it. Active packaging interacts with the food and the environment and, through different mechanisms, prevents its deterioration. These packages contain substances such as oxides, acids, alcohols, peptides, polyphenols, polysaccharides and fatty acids that can absorb or emit gases, regulate humidity, maintain temperature and act as antioxidants and antimicrobials. Within this group of container, smart packaging and edible coatings can be included. The smart packaging contains sensors that provide information on the presence or absence of a substance and others reflect the temperature, freshness and maturation of the food. The coatings, for their part, act as a barrier to gases and can integrate antioxidant and antimicrobial substances that prevent food deterioration. The purpose of this chapter is to provide a general description of active packaging, briefly explaining the different systems under which they work, the substances and the principles on which they are based, their applications, advantages and disadvantages.