A VA nexus letter is a written medical opinion from a qualified health care provider that says whether your current condition is linked to your military service or to another service-connected condition. "Nexus" is VA's word for that link, and it is one of the three things a service-connection claim usually needs. A strong letter gives a clear opinion, often in the words "at least as likely as not," and explains the reasons behind it.
Key takeaways
- VA says a claim usually needs a current disability, an event in service, and a link between them. The nexus letter speaks to the link.
- The writer must be qualified by education, training or experience to give a medical opinion. Doctors, nurse practitioners, physician assistants and psychologists are all examples of providers VA sees on its forms.
- "At least as likely as not" means about a 50% chance or more. "Possible" is not enough.
- Reasoning matters more than a bare conclusion. A letter with no explanation carries little weight.
- A nexus letter is one way to show the link. It never guarantees an outcome.
What is a VA nexus letter?
VA's page on evidence needed for a disability claim lists three things: a current physical or mental disability, an event, injury or disease during service, and a link between the two. For that link, VA says it usually needs medical records or medical opinions from health care providers.
A nexus letter is that medical opinion in letter form. VA lists its general "Medical Opinion" questionnaire as not available for public use, so a nexus letter is usually a letter written by the provider rather than a fill-in VA form.
For a secondary claim, the letter explains how a condition you already have service connection for caused or worsened a new one. For example, one claim might link a sleep problem to PTSD. Our sleep apnea VA claim guide walks through that kind of link.
Who can write a VA nexus letter?
VA's rule in 38 CFR 3.159 says competent medical evidence comes from a person qualified through education, training or experience to offer medical diagnoses, statements or opinions. The title is not what counts. The writer's qualifications for your condition are.
VA's own Disability Benefits Questionnaires show the range of providers it expects. The examiner title line gives examples such as MD, DO, DDS, DMD, Ph.D, Psy.D, NP and PA-C. The same form asks for the provider's specialty, license number and National Provider Identifier.
| Possible writer | When it may fit |
|---|---|
| Your treating doctor | They know your history and have seen you over time |
| A specialist for your condition | The link depends on specialized knowledge, such as a sleep doctor or a cardiologist |
| A psychologist or psychiatrist | The claim is for a mental health condition |
| A nurse practitioner or physician assistant | They treat you regularly and are qualified to give the opinion |
Start by asking the provider you already see. Tell them what the letter needs to cover, and ask about fees up front. VA says it does not pay or reimburse costs of completing a Disability Benefits Questionnaire, so plan on asking about costs.
What should a strong nexus letter say?
A good letter is clear, factual and written in the provider's own words. Here is a checklist to share with your provider.
- Who they are. Name, credentials, specialty, license number and contact information.
- What they reviewed. List the records they looked at, such as service treatment records, VA records and private records.
- The diagnosis. State the current condition and when it was diagnosed.
- The facts from service. Describe the event, injury or service-connected condition in accurate terms that match your records.
- The opinion. State whether it is at least as likely as not that the condition was caused or aggravated by the service event or service-connected condition.
- The reasoning. Explain how the facts connect to the opinion, using medical knowledge. Cite medical research if it helps.
- Other possible causes. Address them, including any earlier opinion that said there was no link.
- Signature and date.
VA's rule says competent medical evidence can also include statements from medical treatises and authoritative medical or scientific articles. A provider may cite them to support the reasoning.
What does "at least as likely as not" mean?
Board of Veterans' Appeals decisions describe it this way: the likelihood is at least approximately balanced or nearly equal, if not higher, or about a 50% probability or more. It is not the same as "possible." The opposite finding is "less likely than not."
The standard connects to VA's benefit-of-the-doubt rule. Under 38 CFR 3.102, when there is an approximate balance of positive and negative evidence, the doubt is resolved in favor of the claimant. That is why a clear opinion at the "at least as likely as not" level can matter.
What to avoid in a VA nexus letter
- Do not use guesswork words. Phrases like "could be," "may be" or "possibly" make an opinion sound speculative. Board decisions treat opinions that rest on mere speculation as inadequate.
- Do not skip the reasons. Board decisions, citing the Veterans Court case Nieves-Rodriguez v. Peake, say most of the probative value of an opinion comes from the discussion of its underlying reasoning.
- Do not let facts drift from your records. Check every date, diagnosis and event in the letter against your files before you send it.
- Do not ignore a negative opinion. In one January 2024 Board decision, the Board gave more weight to a private opinion that tied sleep apnea to PTSD, and rejected a VA opinion that failed to address it. That is one decision, not a rule, but it shows why addressing earlier opinions matters.
- Do not use a one-size-fits-all template. A letter should match your facts and your provider's own judgment.
- Do not pay anyone who promises a rating. No one can guarantee a VA decision, and a provider should only sign an opinion they believe is medically true.
Example wording for a provider (placeholders only)
Example only. A provider must write their own opinion based on their own exam, records review and medical judgment. Do not ask a provider to sign wording they do not agree with.
I am [Provider name], [credentials], and I have treated [Veteran's name] since [date]. I reviewed [list of records]. The Veteran has a diagnosis of [condition], first diagnosed on [date].
It is my medical opinion that it is at least as likely as not (50 percent or greater probability) that [condition] was caused by or aggravated by [service event or service-connected condition]. My reasons are: [explain how the facts and medical knowledge connect, and why other causes are less likely].
[Signature, date, license number, contact information]
Do you always need a nexus letter?
No. A few situations may not call for one.
- Some conditions are presumed linked to service. VA's evidence page says that for certain conditions, such as some chronic illnesses diagnosed within a year after discharge, VA may conclude there is a link without more evidence.
- VA may order its own exam. Under 38 CFR 3.159, VA must provide an exam or opinion in some cases when the record has competent lay or medical evidence of a current diagnosis or recurring symptoms, and the condition may be associated with service.
- Your own records may already show the link. A clear note from a treating provider can sometimes serve the same purpose.
When in doubt, ask an accredited representative. Another useful piece is a buddy statement for a VA claim to describe what others saw. It supports the medical opinion; it does not replace it.
Frequently asked questions
Does VA accept a nexus letter from a private doctor?
Yes. VA says it values evidence from private treatment providers because they know your medical history. VA still weighs the letter with the rest of your evidence.
Can a nurse practitioner or physician assistant write a nexus letter?
VA's rule asks whether the writer is qualified through education, training or experience to give the opinion. VA's questionnaires list NP and PA-C among the titles examiners may use.
What does "at least as likely as not" mean?
Board decisions describe it as a probability of about 50% or more. It means the link is as likely as not, or more likely, and it is stronger than "possible."
Will VA pay for my nexus letter?
VA says it does not pay or reimburse costs of completing a Disability Benefits Questionnaire. Ask any provider about fees before you start.
Can a nexus letter guarantee my claim will be approved?
No. VA reviews all of the evidence in your file. A nexus letter is one piece of that evidence.
Start the free VA claim questionnaire
If you are trying to work out what evidence your claim is missing, you can get free help from an accredited Veterans Service Organization representative; VA says their services on your claims are always free. If you would like support organizing your evidence, see how SustainBL's VA claims support works, then Start the free VA claim questionnaire.
This article is general information, not legal, medical or financial advice. SustainBL is not a law firm and does not guarantee any VA decision.
