Following a brief review of cider making around the world, including data on production levels in Europe and the United Kingdom, the general approach to production of cider from apple juice is considered. The article then addresses the microbiology of cider production, with an emphasis on commercial production, including the need for sulfite treatment of juice to prevent growth of undesirable wild yeasts and other organisms, and the production and use of selected fermentation yeasts. Issues related to the control of pathogenic and spoilage microorganisms derived from the environment are considered as well as the significance of patulin as a mycotoxin formed in mold-spoiled apples. Procedures for production of special kinds of cider are considered, as these differ from general production procedures. Finally, the biochemical changes that occur during fermentation and maturation are discussed in relation to desirable and undesirable flavor constituents.