Purpose. The National Institutes of Health (NIH) Investigator-Initiated Small Grant (R03) funding opportunity supports small research projects that can be carried out in a short period of time with limited resources. Investigator-initiated research, also known as unsolicited research, is research funded as a result of an investigator submitting a research grant application to NIH in an investigators area of interest and competency. All investigator-initiated small grant applications described in this announcement will be assigned to NIH Institutes and Centers (ICs) according to standard Public Health Service (PHS) referral guidelines and specific program interests. Investigators are strongly encouraged to consult the list of participating ICs and special research interests. The R03 grant mechanism supports different types of projects including pilot and feasibility studies; secondary analysis of existing data; small, self-contained research projects; development of research methodology; and development of new research technology. The R03 is intended to support small research projects that can be carried out in a short period of time with limited resources. Mechanism of Support. This FOA will utilize the NIH Small Research Grant (R03) award mechanism Funds Available and Anticipated Number of Awards. Because the nature and scope of the proposed research will vary from application to application, it is anticipated that the size and duration of each award will also vary. The total amount awarded and the number of awards will depend upon the mechanism numbers, quality, duration, and costs of the applications received. Budget and Project Period.The total project period for an application submitted in response to this funding opportunity may not exceed two years. Direct costs are limited to $100,000 direct costs over the R03 2 year period, with no more than $50,000 in direct costs allowed in a single year.