The purpose of this guidance produced by the Pan UK Pharmacy Working Group of ATMPs is to outline the responsibilities of pharmacists where preparation of advanced therapy medicinal products (ATMPs) holding marketing authorisations is required prior to administration in hospitals. Full compliance with the summary of product characteristics (SmPC) requirements is always recommended.  This guidance clarifies where activities require the oversight of a pharmacist and distinguishes circumstances in which preparation under the supervision of a pharmacist would be a legal requirement. It provides definitions and distinction between the use of these terms.