Chronic-Disease Presumption

If a listed chronic disease appears within a specific window after you separate, the VA presumes it is service-connected, without requiring you to prove a specific in-service event caused it. This is the time-since-separation presumption under 38 CFR 3.307(a)(3) and 3.309(a). Different diseases have different windows: one year for most, three years for tuberculosis and Hansen's, seven years for multiple sclerosis, and lifetime for ALS.

Educational reference, not a claim-eligibility ruling. The presumption applies only to veterans who served at least 90 continuous days of active service and whose listed disease manifested to a degree of at least 10 percent within the applicable window. National Guard and Reserve members generally do not qualify unless they have a qualifying period of active duty. The application is to the VA, with medical evidence of the diagnosis and onset date.

The two-part rule

Under 38 CFR 3.307(a)(3) the chronic-disease presumption applies if (1) the veteran served 90 days or more of active service AND (2) the listed disease in 38 CFR 3.309(a) manifested to a compensable degree of at least 10 percent within the timeframe assigned to that disease. ALS gets a separate rule under 38 CFR 3.318 with no manifestation window.

How the presumption works

Service connection normally requires three things: a current diagnosis, an in-service event, and a medical nexus linking the two. The chronic-disease presumption replaces the in-service event and the medical nexus with a regulatory assumption, if the disease is on the 3.309(a) list and manifests within the applicable window.

Two parts:

Manifestation rule (3.307(a)(3)). The disease must show itself to a degree of at least 10 percent within the prescribed window after separation. "Manifest" means the disease was present, not necessarily that it was formally diagnosed.
Listed disease (3.309(a)). The disease must be on the 3.309(a) list (or, for ALS, on the 3.318 list). Conditions not on the list are not presumptive under this rule, but can still be service-connected on a direct or secondary theory.

38 CFR 3.307(a)(3): "Chronic disease. The disease must have become manifest to a degree of 10 percent or more within 1 year (for ALS, no time limit) from the date of separation from service as specified in § 3.309(a)."

Qualifying service

90 continuous days of active service. Required for all chronic-disease presumptions under 3.307(a)(3). Brief active-duty periods (e.g., a single training cycle) do not qualify.
National Guard and Reserve. A period of active duty for training (ADT) or inactive duty training (IADT) generally does not count toward the 90-day requirement. Title 10 federal mobilization can qualify if 90+ days. See the Guard / Reserve claims guide.
Discharge characterization. Must be other than dishonorable (Honorable, General, OTH with VA character-of-discharge determination, etc.). See the record corrections guide if your discharge is currently a bar.

1-year window Most chronic diseases

Manifests to 10 percent or more within one year after separation from qualifying active service.

Arthritis (osteoarthritis, degenerative)
Atherosclerosis
Brain hemorrhage / brain thrombosis
Bronchiectasis
Calculi of kidney, bladder, or gallbladder
Cardiovascular-renal disease (including hypertension)
Cirrhosis of the liver
Coronary thrombosis
Diabetes mellitus
Encephalitis lethargica (residuals)
Endocarditis
Endocrinopathies
Epilepsies
Hodgkin's disease
Leukemia
Lupus erythematosus, systemic
Myasthenia gravis
Myelitis
Myocarditis
Nephritis
Other organic diseases of the nervous system
Osteitis deformans (Paget's disease)
Osteomalacia
Palsy, bulbar
Paralysis agitans (Parkinson's)
Polycythemia vera
Polyneuritis
Psychoses
Purpura idiopathic hemorrhagic
Raynaud's disease
Sarcoidosis
Scleroderma
Tumors, malignant, or of the brain or spinal cord or peripheral nerves
Ulcers, peptic (gastric or duodenal)

Hypertension. Falls under "cardiovascular-renal disease" within the 1-year window. Diagnostic readings of 160 / 100 sustained, or treatment with medication, are typically enough to show the 10-percent manifestation level required by the diagnostic code.

3-year window Tuberculosis and Hansen's

Manifests to 10 percent or more within three years after separation from qualifying active service.

Active tuberculous disease
Hansen's disease (leprosy)

The three-year window reflects the longer incubation period these diseases can have.

7-year window Multiple sclerosis

Manifests to 10 percent or more within seven years after separation from qualifying active service.

Multiple sclerosis (MS)

MS often has a long latency between in-service onset and definitive diagnosis. The seven-year window recognizes that.

Lifetime (no manifestation window) ALS

Under 38 CFR 3.318, amyotrophic lateral sclerosis (ALS) in a veteran with 90+ days of continuous active service is service-connected as a matter of law, no matter how long after service it develops.

Amyotrophic lateral sclerosis (Lou Gehrig's disease)

38 CFR 3.318(a): "The development of ALS manifested at any time after discharge or release from active military, naval, or air service is sufficient to establish service connection for that disease."

Exceptions: the presumption does not apply if there is affirmative evidence the ALS was not service-related or was caused by intervening events, but in practice these exceptions are narrow.

Evidence the VA expects

Current diagnosis. Confirmed by clinical evaluation, imaging, lab work, or biopsy as appropriate for the condition.
Onset date. The earliest date the disease manifested to a 10 percent degree. Treating-physician records that note the date of first complaint or first abnormal finding are typically enough.
Service records. DD-214 confirming the 90+ days of continuous active service and discharge characterization.
Manifestation evidence. Documentation that the condition reached the 10-percent threshold within the applicable window. The threshold is defined by the diagnostic code for that condition.

If the diagnosis itself was made years later but the symptoms can be shown to have started within the window (for example, a multiple-sclerosis diagnosis at year 9 with symptom onset at year 4), the presumption can still apply.

If the presumption does not apply

The presumption is one path to service connection, not the only one. If your disease is not on the 3.309(a) list, manifested outside the window, or you lack 90 days of continuous active service, you can still pursue:

Direct service connection by showing the disease started in service or was caused by an in-service event with a medical nexus opinion. See service connection basics.
Secondary service connection if the disease was caused or aggravated by an already-service-connected condition. See secondary claims.
Exposure-based presumption if your service involved Agent Orange, burn pits, Camp Lejeune water, radiation, or other listed exposures. See the presumptive check tool.

Sources and authority

38 CFR § 3.307 - Presumptive service connection for chronic, tropical, or PoW related disease
38 CFR § 3.309 - Disease subject to presumptive service connection
38 CFR § 3.318 - Presumptive service connection for ALS

Frequently asked questions

I was diagnosed with diabetes 14 months after I separated. Does the 1-year window bar me?

Not necessarily. The rule is when the disease manifested to a 10-percent degree, not when it was diagnosed. If treating-physician records or lab values show abnormal blood sugar or pre-diabetes within the first year after separation, the manifestation date can be the in-window date even if the formal diabetes diagnosis came later. A medical-opinion letter from your treating physician on the manifestation date is often pivotal.

My hypertension was diagnosed at year 2. Can I still use this presumption?

Yes, if you can document the manifestation within the first year. Hypertension manifests in the 10-percent range when systolic is consistently 160+ or diastolic 100+, or when treatment is started. Pre-separation or first-year post-separation readings in that range support the presumption even if the formal diagnosis came later.

I was Guard / Reserve and never had 90 continuous days of active service. Am I excluded from this presumption?

Yes, from this specific presumption. Guard / Reserve members generally need 90+ days of Title 10 active duty for the 3.307(a)(3) chronic-disease presumption to apply. You may still pursue direct service connection if you can link a current chronic disease to a specific in-service event during ADT or IADT. See the Guard / Reserve guide.

What does "to a degree of 10 percent" mean?

Each diagnostic code defines what counts as a 10-percent rating for that condition. For arthritis, it is typically X-ray evidence with painful motion. For hypertension, it is diastolic 100+ or systolic 160+ with continuous medication. For diabetes, it is requiring restricted diet only. The 10-percent threshold is the level of severity the presumption requires the disease to have reached within the window.

Is the 1-year window calendar-strict, or is there any flexibility?

Calendar-strict in terms of the manifestation date, but the VA looks at the date the disease manifested, not the date you noticed it or were diagnosed. Buddy statements from family describing symptom onset can be evidence of in-window manifestation even when contemporaneous medical records do not exist.

What if my disease is not on the 3.309(a) list?

The chronic-disease presumption does not apply, but service connection on direct, secondary, presumptive-exposure, or aggravation theories may still be available. The 3.309(a) list is one of several pathways; not being on it does not mean you have no claim. See the seven paths to service connection.

RateMyVSO. Educational resource. Not affiliated with the U.S. Department of Veterans Affairs. Not legal advice. All RateMyVSO tools are free. Find a VSO representative for personalized guidance.