With the emergence of biosimilars, the development process for these drugs is a topic of increasing interest to medical writers. Even though information and educational documents on the concept of biosimilarity areincreasingly publicly available, it takes some practice for the medical writer to translate the specific requirements into fit-for-purpose documents. This feature article summarises the relevant regulatory requirements for the clinical development of biosimilars. It includes best-practice recommendations on how these requirements can be translated into the everyday work for medical writers.