Each year thousands of biomedical and behavioural researchers submit grant applications to the United States Public Health Service (USPHS) for support of their research or research training activities. The majority of these applications are submitted to the National Institutes of Health (NIH). By describing the inner workings of the NIH extramural programs and providing practical information about grant programs and processes, this authoritative work is designed to help investigators gain a more favourable edge in obtaining support for their research proposals. It offers practical insights into a broad spectrum of the basic and clinical research interests of the 21 NIH research granting components, and identifies the various mechanisms of support. Descriptions, guidance, and advice are also provided on specific areas such as how to prepare a grant application; the peer review system, the procedures leading to award decisions, the responsibilities of the NIH staff in managing the review and referral of applications, and managing grant programs. Other extramural policies and procedures are covered such as the appeals system, animal welfare, the privacy act, and research involving human subjects. Legislation, funding, and the NIH budget are also discussed. Written by two former senior-level managers at the National Institutes of Health and current consultants to several USPHS agencies, A Guide to NIH Grant Programs is a valuable reference source for members of the biomedical and behavioural research community.