Small and Exploratory/Developmental Research Grants SOP

This standard operating procedure (SOP) includes the following sections: Purpose, Procedure, Contacts, and Links.

Some links will work for NIAID staff only.


To support small-scale research projects and encourage exploratory and developmental research.


Small (R03) and exploratory/developmental research (R21) grants are designed for investigators who have small defined projects where preliminary data are not required.

R03s provide investigators with up to $50,000 a year in direct costs for up to two years and do not have any cost-sharing requirements. Below are examples of projects suitable to a small grant:

  • Pilot or feasibility studies
  • Secondary analysis of existing data
  • Small, self-contained research projects
  • Development of research methodology
  • Development of new research technology

R21s provide investigators with up to $275,000 in direct costs for a two-year period, with no more than $200,000 in a single year, unless otherwise specified in the notice of funding opportunity (NOFO). Unlike R03s, R21s are designed to introduce novel scientific ideas, model systems, tools, agents, targets, and technologies that have the potential to substantially advance biomedical research.

NIAID does not allow administrative supplement requests for small and exploratory/developmental research grants, unless specifically called for by a notice of special interest or targeted initiative. Grantees do not need NIAID’s prior approval for the first no-cost extension and carryover on most small and exploratory/developmental research grants.

NIH does not allow principal investigators to renew R03s or R21s.

Investigators who are not highly knowledgeable about NIH activity codes should contact a program officer for help before choosing a small grant. Go to Contacting Program Officers and Grants Management Specialist.

If resubmissions are allowed, applicants may revise and resubmit their applications one time as a resubmission (A1) application. For A1s that do not succeed, applicants may submit the same idea as a new (A0) application for the next appropriate due date. For more information, see Options if Your Application Isn't Funded in Apply for a Grant.

Find active R03 and R21 NOFOs on NIAID’s Funding Opportunities list. 


  • Decide whether to apply for an R03 or R21.
  • Prepare your application according to the instructions in the relevant NOFO linked on NIAID’s Opportunities and Announcements page.
  • Submit your application by the due date in the NOFO.


DAIDS: Madelon Halula

DAIT: Stacy Ferguson


DMID: Samuel Perdue

For notices of funding opportunities, contact the program officer listed in announcements.

Use the contacts listed above for questions about your specific situation. If you have a general question or a suggestion to improve this page, email the Office of Knowledge and Educational Resources at


Apply for a Grant

NIAID Funding Policy and Process SOP

IC-Sponsored Program Announcements (PARs and PASs) SOP

Requests for Applications (RFA) SOP

Comparing Popular Research Project Grants: R01, R03, and R21

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