VA Service Connection Types: Proving Disability Links (2026)

What Service Connection Means

A VA service connection is a factual link between a disability and your military service. You can establish this link with evidence that your military service caused or worsened your condition or illness.

The five VA service connection types are as follows.

Direct Service Connection

A direct service connection is the most common service connection for VA disability claims. This connection type claims that the injury or condition occurred in the performance of military duties as a result of a service-related incident or exposure.

For example, you might pursue a direct service connection for hearing loss caused by an explosion during a live-fire training exercise.

Presumptive Service Connection

Presumptive service connections are typically the easiest to document. They’re reserved for specific conditions tied to specific locations or exposures, such as exposure to Agent Orange in Southeast Asia, burn pits in Afghanistan or Iraq, or tainted water at Camp Lejeune.

Secondary Service Connection

A secondary service connection occurs when an approved service-connected disability causes or worsens a separate injury or condition. For instance, you might receive VA disability benefits for a service-connected knee injury, then establish a secondary service connection if you develop a hip condition from limping on your bad knee.

Service Connection by Aggravation

You can also receive VA benefits for a pre-existing condition that your military service aggravated.

For example, imagine someone who suffered from sports-related back pain when they joined the military. By the time they leave, they have two herniated discs from a service-related vehicle crash that worsened their back pain and caused neuropathy in their legs. Such a person might prove a service connection by aggravation.

Service Connection Under 38 U.S.C. 1151

Section 1151 claims arise when a veteran suffers an injury while receiving VA care or participating in a VA program.

Suppose that you have a torn knee ligament, and a VA doctor mistakenly operates on the wrong knee, resulting in pain and weakness in the previously healthy joint. In this case, you might have a Section 1151 claim.

Evidence You Need to Prove Each Type

For all VA claims, you’ll need a current diagnosis of the condition for which you’re seeking benefits. Additionally, you’ll need proof that you were on active duty, active-duty training, or inactive-duty training when the condition occurred.

Direct and aggravation service connections require evidence explaining how your service caused your condition, such as a VA nexus letter. For secondary and aggravation service connections, you must be able to link your prior condition to the new or worsened condition.

Presumptive claims hinge on military records showing service in the right location at the right time. Finally, for Section 1151 claims, you’ll need evidence that the VA’s actions caused or exacerbated your condition.

By presenting the right type of evidence, you’re more likely to be approved to receive benefits for your service-connected disability.