Many funding agencies allow the use of grants for this purpose and an increasing number, such as the Wellcome Trust, the Howard Hughes Medical Institute and the US National Institutes for Health, strongly encourage open access publication. The following is a list of funding agencies we know of that have confirmed that they allow the payment of article-processing charges:

• Academy of Finland (Finland)
• BIOTEC (Thailand)
• California Institute for Regenerative Medicine (US)
• Canadian Institutes of Health Research (Canada)
• Centre National de la Recherche Scientifique (France)
• Consejo Superior de Investigaciones Cientificas (Spain)
• Consiglio Nazionale delle Ricerche (Italy)
• Danmarks Grundforskningsfond (Denmark)
• Deutsche Forschungsgemeinschaft (Germany)
• FAPESP (Brazil)
• Fondazione Telethon (Italy)
• Fonds zur Forderung der wissenschaftlichen Forschung (Austria)
• Fonds voor Wetenschappelijk Onderzoek (Belgium)
• Health Research Board (Ireland)
• Howard Hughes Medical Institute (US)
• Indian Council of Medical Research (India)
• INSERM (France)
• International Human Frontier Science Program Organization (International)
• Israel Science Foundation (Israel)
• Max Planck Society (Germany)
• Medical Research Council (UK)
• National Health Service (UK)
• National Institutes of Health (US) Are you an NIH grantee? More details
• National Science Foundation (US)
• Natural Environment Research Council (UK)
• Nederlandse Organisatie voor Wetenschappelijk Onderzoek (Netherlands)
• Rockefeller Foundation (US)
• South African Medical Research Council (South Africa)
• Swedish Foundation for Strategic Research (Sweden)
• Swedish Research Council (Sweden)
• Swiss National Science Foundation (Switzerland)
• Wellcome Trust (UK) More details

For more detailed information, see BioMed Central's summary table of biomedical funder policies on open access.