The EMA guideline on quality, non-clinical and clinical aspects of gene therapy medicinal products (GTMP´s) builds on earlier documentation and further specifies requirements for development and Market authoriszation (MAA). The revision addresses the issues identified from previous MAAs, scientific advice and clinical experience with GTMPs and covers legal and technical requirements. Three sections (quality, non-clinical and clinical) are described in detail, and the structure of the document is now aligned with a general CTD format of a MAA. The quality section addresses mainly the specific requirements for the development and manufacture of a GTMP. The non-clinical section addresses the non-clinical studies required to support a marketing authorisation application. The clinical section addresses the requirements for studying the pharmacological properties of the GTMP itself and the transgene product.