What is a Medicare ANOC?
Last reviewed July 2026
A Medicare Annual Notice of Change, or ANOC, is a letter your parent’s Medicare Advantage or Part D drug plan is required to send every fall. It lists exactly what is changing in the plan for next year, so the short answer to “what is this letter” is: it is the one piece of mail that tells you, in writing, what is different before the change takes effect.
Who sends it, and when
According to Medicare.gov, if your parent is in a Medicare plan, the plan itself sends the ANOC each fall, and it should arrive in September. CMS requires plans to get it in the mail by September 30, so members have time to read it before Medicare’s fall enrollment window opens on October 15.
The ANOC is not sent by Medicare or the government. It comes from your parent’s specific plan, because it is describing that plan’s own changes.
What it actually contains
The ANOC compares this year’s plan to next year’s, usually side by side: the monthly premium, the deductible, copays and coinsurance, the drug formulary and its tiers, the out-of-pocket maximum, network changes, and any extra benefits the plan adds or drops. It is a summary of changes, not the whole plan.
ANOC vs. Evidence of Coverage: what is the difference
Around the same time, most plans also send a second, longer document called the Evidence of Coverage (EOC). Medicare.gov describes the EOC as the document that gives you details about what the plan covers, how much you pay, and more. Where the ANOC is a short list of what is changing, the EOC is the full reference for how the plan works all year. If your parent gets only one in the mail, contact the plan; both are required.
Why it is worth reading
The changes an ANOC lists take effect January 1. Medicare’s fall Open Enrollment Period, October 15 through December 7, is the window to act on them if your parent wants to change plans; it is also the only real chance to catch a rising premium or a dropped medication before the new plan year starts.
Whether to act on any change is a personal decision. We do not make it for you and we do not compare plans. For personalized, unbiased help, Medicare’s official Plan Finder and your State Health Insurance Assistance Program (SHIP) are free and independent.
Have your parent’s ANOC in hand? Upload it and we’ll pull out exactly what changed, in plain language, each point cited to the page it came from.
Decode the notice, freeNoticeOfChange explains what your parent’s notice says and organizes the deadlines. We are not insurance agents or advisors, we do not recommend or compare plans, and we are not affiliated with Medicare or CMS.