NIH funds individual research training primarily through the Ruth L. Kirschstein National Research Service Award (NRSA) program, established under Title I of the National Research Act of 1974 (Public Law 93-348). Within NRSA, awards split into two structural forms: institutional training grants, where a department or program (the “T” series, e.g. T32) holds the award and nominates trainees into funded slots, and individual fellowships, where the trainee or fellow is personally the named Principal Investigator on their own award. This guide covers the individual-fellowship “F” series — F30, F31, F32, and F33 — and how the four mechanisms map onto career stage.
Each F-series mechanism targets a different, non-overlapping stage of a research career. Confusing them is a common early mistake for applicants and research administrators new to NIH training mechanisms, since all four share the same statutory NRSA authority, similar stipend structures, and overlapping application components — but eligibility, the required training plan, and the review criteria differ by mechanism.
The F30/F31/F32/F33 Family at a Glance
| Mechanism | Career stage | Who applies | Typical duration |
|---|---|---|---|
| F30 | Predoctoral, dual-degree | Students matriculated in a combined research-doctorate/clinical-doctorate program (MD/PhD and equivalents such as DO/PhD, DDS/PhD, DVM/PhD, PharmD/PhD, AuD/PhD) | Up to 5 years, covering the PhD-research phase of the dual-degree program |
| F31 | Predoctoral, single-degree | Students enrolled in a research doctoral program (e.g. PhD) who have reached the dissertation-research stage; a parallel F31–Diversity track exists for candidates from groups NIH has identified as underrepresented in biomedical research | Up to 5 years, covering the dissertation-research phase |
| F32 | Postdoctoral | Individuals who already hold a qualifying doctoral degree, applying for mentored training under a named faculty sponsor, typically at an institution other than the one that granted their doctorate | 1–3 years |
| F33 | Senior/established investigator | Established scientists seeking a structured period of protected time to acquire new research skills or redirect their research — not a first-time training award | Typically shorter, protected-time award; specific terms set by the issuing NIH Institute/Center’s funding opportunity |
All four are individual awards: unlike a T32 slot, the applicant — not their department or training program — is the fellowship’s own Principal Investigator, working with a named faculty sponsor and an individualized research training plan specific to that applicant.
F30: Predoctoral Fellowship for Dual-Degree Students
The F30 (formally the NRSA Individual Predoctoral Fellowship for students in combined MD/PhD or other dual-doctoral-degree training programs) supports students pursuing an integrated research and clinical training plan, most commonly MD/PhD candidates aiming toward a physician-scientist career, but also parallel dual-degree tracks such as DO/PhD, DDS/PhD, DVM/PhD, PharmD/PhD, and AuD/PhD. The application must describe both the dissertation research project and how it integrates with the applicant’s clinical training. NIH issues separate parent funding opportunity announcements depending on whether the applicant’s institution already holds an NIH-funded institutional predoctoral dual-degree training program.
F31: Predoctoral Fellowship for Dissertation Research
The F31 supports predoctoral students in a single research-doctorate program (most commonly a PhD) who have advanced to the dissertation-research stage, applying directly with a named faculty sponsor to fund the final years of dissertation work. It is the individual-fellowship mechanism most directly comparable to F32 at the postdoctoral stage — and one of the most common points of confusion, since both are individual NRSA fellowships with a mentored training plan and a named sponsor, differing chiefly in whether the applicant has completed the doctorate. CASRAI’s F31 vs. F32 comparison covers that distinction in more detail. A parallel F31–Diversity track uses the same dissertation-stage and enrollment eligibility as the standard F31, applied under NIH’s diversity-specific funding opportunity parameters.
F32: Postdoctoral Fellowship
The F32 funds an individual who already holds a qualifying doctoral degree (PhD, MD, or equivalent) to pursue a defined, mentored postdoctoral research training plan under a named faculty sponsor — typically, though not always, at a different institution from the one that granted the doctorate. It is distinct from a K99/R00 Pathway to Independence award, which funds a bridge from mentored postdoctoral training into an independent faculty research program, and from simply being paid as postdoctoral staff on a mentor’s own R01. See CASRAI’s F32 dictionary entry for the full operational definition and examples.
F33: Senior Fellowship
The F33 is the least commonly encountered mechanism in the family: it supports established, senior scientists rather than trainees at the start of a research career, funding a structured period of protected time to acquire new research skills, techniques, or a substantive change in research direction under an experienced sponsor. Because it is aimed at investigators who already hold a permanent faculty or research position, its stipend is calculated differently from the other three mechanisms — commensurate with the salary the applicant’s home institution would otherwise pay — rather than the standard NRSA predoctoral/postdoctoral stipend scale. The specific eligibility bar (years of independent research experience, sabbatical framing) and the exact funding opportunity vary by the NIH Institute or Center issuing the award; consult that IC’s own current funding opportunity announcement before applying.
What All Four Mechanisms Share
- Individual PI status. The applicant, not an institution or department, is the fellowship’s own Principal Investigator.
- A named faculty sponsor who commits to providing mentored research training and whose own track record and institutional resources are themselves reviewed as part of the application.
- An individualized research training plan, distinct from a standard R-series research strategy, that describes both the science and the training/career-development activities.
- NRSA stipend and allowance structure. All four mechanisms pay a training stipend rather than a PI salary charged to direct research costs, at levels NIH revises annually by Guide notice — see CASRAI’s NRSA Stipend Levels entry for how that scale works and where the current notice is published.
- Payback service obligation. Postdoctoral NRSA support (F32, F33, and postdoctoral T-series awards) carries a service payback obligation for the first 12 months of support, discharged through further NRSA-supported training, health-related research, or health-related teaching, averaging at least 20 hours per week. Predoctoral NRSA support (F30, F31) carries no payback obligation.
- Citizenship/residency requirement. Kirschstein-NRSA support, across both the F and T series, is restricted to U.S. citizens, non-citizen nationals, or individuals lawfully admitted for permanent residence at the time of award.
Choosing the Right Mechanism
The decision generally follows directly from career stage and degree pathway rather than judgment about strength of the research plan:
- Enrolled in a combined MD/PhD or other dual-doctoral-degree program, applying for the PhD-research phase → F30.
- Enrolled in a single research-doctorate program, at the dissertation-research stage → F31 (or F31–Diversity, if eligible).
- Already hold a qualifying doctorate, seeking mentored postdoctoral research training → F32.
- Already an established, independently funded investigator, seeking protected time for a defined skills-acquisition or research-redirection plan → F33.
- A department or program wants to fund several trainees at once, rather than a single named individual applying as their own PI → none of the F-series; that is a T32 institutional training grant instead.
Applicants and the sponsored-programs or fellowships office supporting them should always confirm current eligibility, deadlines, and stipend levels against the specific funding opportunity announcement issued by the relevant NIH Institute or Center — individual ICs can add participation restrictions or narrow an FOA’s scope beyond the general parent-announcement eligibility described here, and NRSA stipend levels are revised annually by NIH Guide notice.
Frequently Asked Questions
What does NRSA stand for and how does it relate to F30/F31/F32/F33?
NRSA stands for National Research Service Award, formally the Ruth L. Kirschstein National Research Service Award, the statutory training-support authority created by the National Research Act of 1974. F30, F31, F32, and F33 are the individual-fellowship (“F” series) mechanisms funded under that authority; the parallel institutional (“T” series, e.g. T32) mechanisms are also NRSA awards but held by an institution rather than by the individual trainee.
Can I apply for both an F31 and a T32-funded slot?
An individual cannot simultaneously hold both an individual NRSA fellowship and an institutional NRSA training-grant slot for the same period of support — NRSA rules generally prohibit concurrent NRSA support from more than one award. A trainee already in a T32-funded slot may separately apply for an F31 to fund a later, defined phase of dissertation research, but would transition off the T32 slot rather than hold both at once; check the specific program’s and institution’s own policy before assuming this is automatic.
Do F-series fellowships pay tuition?
NRSA individual fellowships include a tuition and fees allowance in addition to the trainee/fellow stipend, though the allowance amount and whether it covers tuition in full depends on the institution and the annual NIH Guide notice setting NRSA budgetary levels for that fiscal year — see CASRAI’s NRSA Stipend Levels entry.
Is an F32 the same as a K99/R00 award?
No. An F32 funds mentored postdoctoral training under a faculty sponsor; a K99/R00 is a career-development, not NRSA, mechanism designed specifically to bridge an outstanding postdoctoral researcher from mentored training (the K99 phase) into an independent faculty research position (the R00 phase). Applicants sometimes hold an F32 earlier in their postdoctoral training and a K99/R00 later, but the two are structurally distinct award types with different review criteria.
Who can apply for NRSA fellowships?
NRSA support, across the F and T series, is restricted to U.S. citizens, non-citizen nationals, or individuals lawfully admitted for permanent residence in the United States at the time of award. Applicants who do not meet that residency/citizenship requirement should look to non-NRSA NIH mechanisms or non-NIH funders instead.
