The Importance Of A VA Nexus Letter For A Claim (2026)

What a Nexus Letter Is

A VA nexus letter is a formal medical opinion that must be written by a licensed healthcare professional to clearly connect a currently diagnosed condition to an event, injury or illness that occurred during military service.

For the majority of VA claims, except those that involve PACT Act presumptive conditions, you will need this type of document.

When You Need a Nexus Letter

You will need a VA nexus letter in any instance when you’re trying to demonstrate a connection between your service and your disability. That is often the case when there are no in-service medical records that show a diagnosis.

Another instance when you need these letters is when trying to establish secondary service connections when a primary disability worsened or caused a new condition.

If you are going for a VA rating increase because of a secondary condition, you may not need this letter. The same is true if you have available records of an in-service diagnosis of the condition.

The Three Elements It Must Prove

A VA nexus letter must prove that you have received a clear and current diagnosis. It must state that you suffer from a chronic disability.

The letter must also present your history in service and connect it to an injury, event or stressor. It must cite specific dates and locations or how you sustained an injury. Finally, the letter must offer a nexus, or a medical causation link, between the in-service event and your current disability.

What a Strong Nexus Letter Contains

A strong VA nexus letter must state the physician’s credentials and expertise. It should offer proof of medical review. The doctor must state that they reviewed all available evidence and performed assessments regarding your condition. There should be a mention of the progression of the condition, with clear dates and timelines.

It’s helpful for the physician to also mention that they read buddy letters and other layperson evidence. This can show that the physician did a comprehensive assessment.

There should also be a clear and formal diagnosis that leaves no room for ambiguity. For mental health conditions, the letter must mention standard medical texts, like the DSM-5.

The “At Least as Likely as Not” Standard

This is the evidentiary threshold the VA uses for its claims. It states that the claimant must demonstrate a 50% or greater likelihood that their medical condition is connected to their service.

If the evidence in these cases balances out to 50/50, the benefit-of-the-doubt rule comes into play. The VA will typically grant the requested benefits.

Who Can Write Your Nexus Letter?

A nexus letter can be written by any healthcare professional who has the right level of experience and training. This can include:

• Doctors
• Doctors of osteopathy
• Nurse practitioners
• Physician assistants
• Psychologists
• Specialists

The VA tends to value the letters more if they are written by board-certified specialists with experience in treating the exact condition you have.

How to Get a Better Nexus Letter

To get the highest quality nexus letter possible, you must take your time choosing the right medical expert. Prioritize specialists and choose doctors over nurses, if possible. Provide as much documentation to the physician as you can and organize it for them so that they can have quick access to all of the information they need.

Remind the person writing the letter about the VA’s strict language standards. Using phrases like “at least as likely as not,” “highly likely” and “more likely than not” can all help your claim.

Ensure the letter includes an explanation of how the in-service event resulted in your condition. Strengthening that connection gives you the best chance to have your claim approved.

Why Nexus Letters Get Rejected

The VA can reject nexus letters if they don’t meet its standards. If the letter uses incorrect legal terminology and relies on speculative language, it’s likely to be rejected. Additionally, if the letter does not explicitly use the phrase “at least as likely as not,” it is not seen as having met the legal threshold.

Rejections can occur if the letter doesn't offer medical reasoning for the conclusion it reaches or doesn’t cite literature to corroborate the claims. If there is no obvious review of the medical history or the person’s credentials are not sufficient, the VA will reject the letter.

Presumptive Conditions and the PACT Act

There are certain conditions that are presumed to be service-related. Typically, these involve exposure to toxic substances, like Agent Orange. For claims involving presumptive conditions, which are all listed in the PACT Act, it’s generally not necessary to have a nexus letter.

Providing Appropriate Evidence With a Nexus Letter

By ensuring you have a well-written and strong nexus letter, you improve your chances of the VA approving your claim. Take the time to read examples and choose the right person to write it so that your claim is as sturdy as possible.