The Office of Research on Women's Health (ORWH) and cosponsoring Institutes and Offices (IC) of the National Institutes of Health (NIH) invite submission of investigator-initiated research grant applications to support research on the epidemiology, diagnosis, pathophysiology, and treatment of chronic fatigue syndrome (CFS) in diverse groups and across the life span. The total amount to be awarded and the anticipated number of individual awards depend upon the number of meritorious applications received and reviewed. This PA will use the NIH R01, R21 and R03 mechanisms. Organizations that are eligible for this program include domestic non-profit organizations; public or private institutions, such as universities, colleges, hospitals, and laboratories; units of state and local governments; and eligible agencies of the Federal government. There is no specific eligibility requirement for individuals to become Principal Investigators (PI); refer to eligibility information in Section III 1B. Applications must be prepared using the PHS 398 application form which can be downloaded at http://grants.nih.gov/grants/funding/phs398/phs398.html. There is no limit to the number of applications an applicant may submit under this announcement. Telecommunications for the hearing impaired: TTY 301 451-0088.