On 19-21 January 2011, an international expert workshop entitled "Rift Valley fever vaccine development, progress and constraints" was held at FAO Headquarters, Rome, organized under the umbrella of the Global Framework for the Progressive Control of Transboundary Animal Diseases, a joint initiative of FAO and the World Organisation for Animal Health (OIE). The workshop brought together leading experts and policy-makers in Rift Valley fever (RVF) virology, epidemiology and vaccine development. Its objective was to gain consensus and make recommendations on the desired features of novel veterinary RVF virus vaccines, and explore how incentives can be established to assure that these vaccines come to market. The proceedings are now available at http://www.fao.org/ag/againfo/programmes/en/empres/RVF_2011.html or contact [email protected] for more information. RVF is one of the most serious transboundary animal diseases (i.e. epidemic diseases that are highly contagious or transmissible and have the potential for very rapid spread, irrespective of national borders, and can have serious socio-economic and public health consequences). It is a mosquito-borne viral disease, which causes periodic severe epidemics, mainly involving ruminant animals (sheep, cattle and goats). It is also transmitted to humans causing a potentially fatal disease. Control of RVF outbreaks includes vaccination of susceptible animals and two vaccines are currently available, although each has significant drawbacks. There is a widely recognized need to develop safer and more efficacious vaccines for animals.