Service connection is the legal finding that your disability is linked to your military service. Without it, there is no rating and no compensation. Under 38 CFR Part 3, there are several distinct ways to establish it.

What Is Service Connection? The Foundation of Every Claim
Albert Thombs
Founder & VA-Accredited Claims Agent · #45147
Every rating starts with service connection. Here are the five ways to establish it, and why most veterans only know one.

The five pathways
- Direct (§ 3.303): the condition began in or was caused by service.
- Secondary (§ 3.310): a service-connected condition caused or aggravated another.
- Presumptive (§§ 3.307/3.309 + PACT Act): the law presumes a link for certain exposures and conditions.
- Aggravation (§ 3.306): service permanently worsened a pre-existing condition.
- Section 1151: injury caused by VA medical care.
Why this matters
Many veterans only try the direct route, get denied, and give up, when a secondary or presumptive pathway would have won. Part 3 gets you in the door; Part 4 (the rating schedule) decides the percentage once you are connected.
The entire framework governing VA disability compensation is codified in Title 38 of the Code of Federal Regulations, with the rating schedule at 38 CFR Part 4 and the service-connection standards at §3.303 (direct), §3.310 (secondary), and §3.306 (aggravation). Raters adjudicate claims using the procedures in M21-1, the VA's internal manual that tells them exactly what evidence to develop, what exams to order, and how to apply the rating schedule. Under Gilbert v. Derwinski, when the evidence is in approximate balance, every doubt must be resolved in your favor. Under Caluza v. Brown, service connection requires three elements: a current disability, an in-service event, and a medical nexus linking the two, miss any one, and the claim fails.










