This report presents the recommendations of a WHO Expert Committee commissioned to coordinate activities leading to the adoption of international recommendations for the production and control of vaccines and other biological substances, and the establishment of international biological reference materials. Following a brief introduction, the report summarizes a number of general issues brought to the attention of the Committee. The next part of the report, of particular relevance to manufacturers and national regulatory authorities, outlines the discussions held on the development and adoption of new and revised WHO Recommendations, Guidelines and guidance documents. Following these discussions, WHO Guidelines on the quality, safety and efficacy of respiratory syncytial virus vaccines; and an Amendment document to the WHO Recommendations to assure the quality, safety and efficacy of poliomyelitis vaccines (inactivated) were adopted on the recommendation of the Committee. Subsequent sections of the report provide information on the current status, proposed development and establishment of international reference materials in the areas of: antibiotics; biotherapeutics other than blood products; blood products and related substances; cellular and gene therapies; in vitro diagnostics; and vaccines and related substances. A series of annexes are then presented which include an updated list of all WHO Recommendations, Guidelines and other documents on biological substances used in medicine (Annex 1).