For veterans seeking VA disability compensation, service connection is the foundation of every successful VA claim. Without service connection, the VA will deny benefits no matter how serious, painful, or life-altering a condition may be.
Service connection means proving that your current disability is linked to your military service. While the concept sounds straightforward, the reality is far more complex. Many VA claims fail not because the condition isn’t real, but because veterans don’t understand how the VA legally evaluates service connection or what evidence is required.
The VA’s decisions are governed by 38 CFR § 3.303 (Principles Relating to Service Connection) and detailed internal guidance in the M21-1 Adjudication Manual. Understanding these rules and using them strategically can dramatically improve your chances of approval.
“Service connection isn’t about telling your story it’s about proving it under VA law.” Brian Reese, VA Disability Expert
This guide breaks down the five legally recognized paths to VA service connection, explains what evidence works best, and highlights common mistakes veterans make along the way.
Overview: Types of VA Service Connection
| Type of Service Connection | What It Means | Key Evidence Required |
|---|---|---|
| Direct Service Connection | Disability directly caused by military service | Diagnosis, in-service event, nexus |
| Presumptive Service Connection | VA automatically assumes service connection | Qualifying service + diagnosis |
| Secondary Service Connection | Condition caused or worsened by another SC disability | Primary SC condition + nexus |
| Service Connection by Aggravation | Pre-existing condition worsened by service | Medical proof of worsening |
| 38 U.S.C. § 1151 | Disability caused by VA medical care | Evidence of VA negligence |
1. Direct Service Connection
“The Most Common and Straightforward Path”
Direct service connection applies when a veteran’s disability is directly caused by an injury, illness, or event that occurred during military service. This is the most frequently used and best understood type of service connection.
Eligibility Criteria (38 CFR § 3.303)
To win a direct service connection claim, you must establish four elements:
- A current medical diagnosis
- Evidence of an in-service event, injury, or illness
- A medical nexus linking the two
- Current symptoms that impact your work, life, or social functioning
“A diagnosis alone is not enough the VA must see a clear medical link to service.” Brian Reese
Example:
A veteran injures their shoulder during airborne training. Years later, they develop chronic rotator cuff damage and arthritis. A medical opinion confirms the current condition is linked to the in-service injury. This qualifies for direct service connection.
Pro Tip:
If your injury was never formally documented in service, buddy statements (VA Form 21-10210) and a strong private nexus letter can fill the gap especially if you’ve been out of service for more than 12 months.
2. Presumptive Service Connection
“No Nexus Required—The VA Assumes It”
Presumptive service connection is one of the most powerful tools available to veterans. Under 38 CFR §§ 3.307 and 3.309, the VA automatically assumes that certain conditions are related to specific service locations, time periods, or toxic exposures.
“Presumptive service connection exists because science already proved the link.” VA Claims Insider Editorial Team
Common Presumptive Categories Include:
- Agent Orange exposure
- Burn pits and toxic exposure (PACT Act)
- Gulf War illness
- Former POW conditions
Example:
A Vietnam veteran diagnosed with ischemic heart disease does not need to prove exposure to Agent Orange. The VA presumes exposure and grants service connection automatically.
Pro Tip:
Presumptive lists change frequently. Veterans previously denied should reapply when new conditions are added.
3. Secondary Service Connection
“When One Condition Leads to Another”
Secondary service connection applies when a service-connected disability causes or aggravates another condition. This pathway is governed by 38 CFR § 3.310 and is one of the most effective ways to increase a VA rating.
Eligibility Criteria
- A primary service-connected condition (rated 0% or higher)
- A secondary condition that developed because of it
- Medical nexus evidence linking the two
“Secondary claims are often the fastest way to raise a veteran’s VA rating.” Brian Reese
Examples of Common Secondary Conditions:
- PTSD → sleep apnea, migraines, GERD
- Knee injury → back or hip conditions
- Diabetes → neuropathy or kidney disease
4. Service Connection by Aggravation
“When Military Service Makes a Pre-Existing Condition Worse”
Under 38 CFR § 3.306, veterans may receive compensation if military service permanently worsened a pre-existing condition beyond its natural progression.
“Temporary flare-ups don’t qualify the VA looks for permanent worsening.” VA Disability Legal Analysts
Example:
A veteran enters service with mild asthma. After burn pit exposure, the condition becomes severe and chronic. Medical evidence confirms service accelerated the disease. The VA may grant service connection by aggravation.
5. Service Connection Under 38 U.S.C. § 1151
“When VA Medical Treatment Causes Harm”
This rare but critical pathway allows compensation when VA healthcare itself causes or worsens a disability.
“These claims are difficult but extremely powerful when proven.” Veterans Law Attorney Commentary
Evidence That Strengthens Any VA Claim
Helpful evidence includes:
- VA and private medical records
- Nexus letters using VA legal language
- Lay statements from family or coworkers
- DBQs documenting symptom severity
“If it isn’t documented, the VA assumes it didn’t happen.” VA Claims Insider
FAQs
What is VA service connection?
Proof that your disability is linked to military service.
Which type is easiest to win?
Presumptive service connection.
Do I always need a nexus letter?
Yes, except for presumptive claims.
Can secondary claims increase my rating?
Yes, often significantly.
What if my claim is denied?
You can appeal or submit new evidence.
