Biosimilar products are follow-on versions of approved, innovative biopharmaceuticals derived from recombinant DNA technology. As innovator biopharmaceuticals are reaching the end of their patent protection period, there is an increased interest globally in the pharmaceutical industry in the opportunity for the development and registration of biosimilar products. A number of biosimilar products are now approved in certain regions (e.g., Europe), and numerous regulatory authorities around the world have either finalized or are in the process of developing guidance documents for the approval biosimilars. This symposium will provide an overview of the history and development of the regional guidelines for biosimilars, as well as some of the unique challenges in developing biosimilars such as CMC, nonclinical, and clinical issues. Currently approved biosimilar products will be reviewed, including a more in-depth outline of the nonclinical and clinical studies conducted to support the approval of certain biosimilar products to illustrate selected challenges in the development process. The session will also include an overview of the US Biologics Price Competition and Innovation Act and regulatory perspective on requirements for biosimilar development, as well as an update and review on the US FDA’s regulatory guidance on the nonclinical and clinical approval requirements for biosimilars.