Changes to the terms of marketing authorisations for medicinal products, called variations in Europe, must be notified to or approved by the relevant regulatory authorities. Variations include changes to the composition of products, their manufacturing processes, the way they are used, or the indications for which they are authorised. Common approaches are adopted within the European Economic Area to variations to licences approved through the Centralised, Decentralised or Mutual Recognition Procedures. Recent legislation has substantially modified the regulatory requirements and extended them to purely national authorisations by member states. This module, which is fully up to date with the new legislation, covers the classification of variations into their several types and the regulatory requirements, guidance and procedures to be followed for each type.