A nexus letter is a medical opinion written by a qualified healthcare provider that explains how a veteran’s current medical condition is connected to their military service.

In VA disability claims, “nexus” simply means a link or connection. The letter provides a professional medical explanation showing that a condition was caused by, worsened by, or is secondary to events, injuries, or exposures that occurred during service.

Why Veterans Need a Nexus Letter

To grant service connection, the VA generally requires three things

1. A current diagnosed medical condition.

2. Evidence of an in-service event, injury, or illness.

3. A medical link between the two.

Many claims are denied because the third requirement — the medical connection — is not clearly documented.

A nexus letter helps bridge that gap.

A properly written nexus letter:

1. Reviews the veteran’s medical and service records.

2. Explains how service events relate to the current condition.

3. Provides medical reasoning supporting the connection.

4. Uses language aligned with VA evaluation standards.

This medical opinion can be critical for:

• Supplemental claims after denial

• Appeals

• Secondary condition claims

• Conditions that develop years after service

• New Conditions

The Goal of a Nexus Letter

1. The purpose is not to guarantee approval, but to ensure the VA has clear, professional medical evidence to fairly evaluate whether a veteran’s condition is related to their service.

2. When properly supported by records and medical rationale, a nexus letter can significantly strengthen a veteran’s claim for service connection.

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