Insurance appeal letter for a denied claim
Updated October 1, 2026 · How we write our guides
When to use it
Use this letter to ask your health plan to review a denied claim. That's called an internal appeal. For most private plans, you have 180 days from the denial notice to file. Fill in the blanks, answer the reason your plan gave, attach your doctor's letter and records, and keep a copy.
Your health plan denied a claim, and you think it made the wrong call. This letter asks your plan to take a full second look. That's called an internal appeal. For the whole process, see our guide on how to appeal an insurance denial.
When to use this letter
Use it when your plan made a decision you disagree with. That includes denials for medical necessity, coverage, experimental treatment, or network status.
Some denials are billing mistakes, like a wrong code or member ID. The provider can usually fix those with a corrected claim, so you don't need to appeal. Our guide to claim denial codes explained helps you tell which you have.
If your plan said no to care before you got it, use our prior authorization appeal letter instead.
Check your deadline first
For most private plans, you have 180 days from getting the denial notice to file. Your notice should list your deadline and where to send your appeal. Our appeal deadline calculator can help you count.
Medicare, Medicare Advantage, and Medicaid have their own forms and deadlines. If you have 1 of those, follow the steps on your notice.
What to fill in
Type your details into the fields, or edit a copy by hand. Here's where to find each item:
- Member ID: on your insurance card.
- Claim number, dates, and denial reason: on your denial letter or explanation of benefits (EOB).
- Why you disagree: answer the exact reason your plan gave, in plain words. For example: "I tried 2 other treatments first, and neither one worked."
- Your plan's own words: quote the part of your plan documents that covers the care. Your benefits booklet or member handbook usually has it.
If you're writing for someone else, like a parent, your plan may ask for a signed form that lets you act for them. Call member services to ask.
Your letter
Highlighted words are blanks you haven't filled in yet.
What to attach
Send copies, not originals. Include:
- The denial letter or EOB
- A letter from your doctor that answers the denial reason
- Medical records that back up the doctor's letter, like test results and visit notes
- Any bills for the care
How to send it
Follow the instructions on your denial notice. Many plans take appeals by mail, by fax, or through an online member portal.
- By mail: use certified mail with a return receipt. It shows the date your plan got your appeal.
- By portal or fax: save the confirmation page or fax receipt.
- Either way: keep a copy of the letter and everything you attached.
Then call the provider's billing office. Tell them you've appealed, and ask them to hold the bill while you wait.
What happens next
For most private plans, your plan must decide within 30 days for care you haven't gotten yet. For care you already got, it has 60 days. Write down the date your plan got your appeal. If the deadline passes, call and ask for the status.
If your plan says no again, you can often ask for an independent external review. You have 4 months after the final denial to ask. Our external review request letter and our guide to external review for health insurance explain the next step.
Common questions
How long do I have to file an internal appeal?
For most private plans, you have 180 days from the day you get the denial notice. Your notice should list your deadline and where to send your appeal. Medicare, Medicare Advantage, and Medicaid use their own forms and deadlines, so follow the steps on your notice. Send your appeal early if you can, so there's time to fix any gaps.
How long does my plan have to decide?
For most private plans, your plan must decide within 30 days for care you haven't gotten yet. For care you already got, it has 60 days. If waiting could seriously harm your health, ask for an urgent appeal, and most private plans must decide within 72 hours. Some employer plans have 2 levels of appeal, each with shorter time limits.
Do I need a letter from my doctor?
It isn't always required, but it often helps the most. A strong doctor's letter answers the exact reason your plan gave. It explains your diagnosis, why you needed the care, and what else you've tried. Ask the office early, and tell them the date your appeal is due.
What if my plan says no again?
You can often ask for an external review. An independent reviewer that isn't part of your plan looks at your case. You have 4 months after the final denial to ask. If the reviewer sides with you, your plan must accept the decision. Our external review request letter helps you ask.
Sources
- Internal appeals, HealthCare.gov. Accessed October 1, 2026.
- Filing a claim for your health benefits, U.S. Department of Labor, Employee Benefits Security Administration. Accessed October 1, 2026.
- External review, HealthCare.gov. Accessed October 1, 2026.
Related guides
- Start hereHow to appeal a health insurance denialA denied claim isn't the final word. Learn how to appeal an insurance denial, from internal appeal to external review, with deadlines for each plan type.
- GuideDenial codes on your EOB, explainedWhat do CO-45, PR-1, and CO-16 mean? Look up common claim denial codes, learn who's responsible for each amount, and see what to do about each one.
- GuideInsurance didn't pay my medical bill: what to do nextInsurance didn't pay your medical bill? Find out why, match the denial code to the fix, and learn when to ask for a rebill and when to file an appeal.
This is general information, not legal or medical advice. Rules can depend on your plan and your state. Romi Care isn't an insurer, law firm, collection agency, or government program.