Guides · Last reviewed October 20, 2026
How to appeal an Aetna claim denial
Aetna gives most members 180 days from the denial notice to appeal — and you can appeal by phone or in writing. If the internal appeals are denied, you can ask for an independent external review whose decision is binding.
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Why it's worth appealing
Across ACA Marketplace insurers, about 19% of in-network claims were denied in 2024, yet patients appealed fewer than 1% of those denials. When people did appeal, roughly one in three internal appeals ended with the denial overturned.
Step 1: Read your denial letter and EOB
Find the claim number, your member ID, the exact reason for the denial, and the appeal deadline. Common reasons include "not medically necessary," "out of network," "no prior authorization," "experimental," or a provider coding error.
Step 2: Know your deadline (usually 180 days)
Aetna states you have 180 days to appeal from when you get notice of the denied claim, unless your plan brochure or Summary Plan Description gives you more time.
Step 3: Build your case
Request the records and plan criteria Aetna used to decide your claim, and get a letter of medical necessity from your doctor explaining your diagnosis, what was tried before, and why this care was needed.
Step 4: File the appeal with Aetna
You can appeal orally or in writing:
- Call Member Services at the number on your Aetna ID card — Aetna accepts appeals by phone or in writing.
- Check your Explanation of Benefits (EOB) for the mailing address.
- Use Aetna's member Complaint and Appeal Form (linked from your member site).
Aetna sends an acknowledgment within about 5 business days. How fast it decides depends on whether your plan has one or two appeal levels:
- Before care (pre-service): 30 days (15 days if your plan has two appeal levels). Expedited urgent appeals: 72 hours (36 hours for two-level plans).
- After care (post-service): 60 days (30 days if your plan has two appeal levels).
Keep copies and send anything in writing in a way you can track.
Step 5: Request an external review if denied
After you've used Aetna's internal appeals, you may qualify for an external review by an independent third party. That reviewer's decision is binding on the insurer, and the federal process is free.
Where to get free help
- Job-based plan that's self-insured: U.S. Department of Labor, EBSA — 1-866-444-3272.
- Job-based plan that's fully insured: HHS Health Insurance Assistance Team — 1-888-393-2789.
- Medicare: 1-800-MEDICARE, or see our Medicare appeal guide.
For the general step-by-step that applies to any insurer, see our guide to appealing a health insurance denial.
Common questions
How long do I have to appeal an Aetna denial?
You generally have 180 days from the date you get notice of the denied claim, unless your plan documents allow more time.
Can I appeal an Aetna denial by phone?
Yes. Aetna accepts appeals by phone (Member Services) or in writing. A written appeal with records attached creates a clearer paper trail.
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Sources
- Aetna: Claim Denial Resources for Members
- HealthCare.gov: Internal appeals
- HealthCare.gov: External review
- KFF: Claims denials and appeals in ACA Marketplace plans in 2024
Billmira is a self-help information tool, not a law firm, and this isn't legal or medical advice. Billmira is not affiliated with or endorsed by Aetna. Rules change and plans differ; check the official sources above and your own documents.