The International Mouse Phenotyping Consortium (IMPC) is an international scientific endeavour to create and characterize the phenotype of 20,000 knockout mouse strains. Launched in September 2011, the consortium consists of over 15 research institutes across four continents with funding provided by the NIH, European national governments and the partner institutions. The phenotypic data is recorded in a freely accessible, fully searchable online database, generating what has been described as a "comprehensive encyclopaedia of mammalian gene function."