Letter 3064C: A Custom IRS Reply, Not a Standard Notice
By Forrest Baumhover, CFP®, EA · Last verified September 19, 2026
Letter 3064C is the IRS's all-purpose custom reply: an employee writes the body for your specific case, so the number tells you the format but not the subject. What it means, and whether it has a deadline, depends entirely on the paragraphs inside it.
If you got this letter
Got a Letter 3064C in the Mail?
Short version: Letter 3064C is not one specific notice. It is a blank-form custom letter the IRS uses when no standard letter fits your situation, and the person who wrote it typed the message just for you. So the code alone tells you nothing about what the IRS wants.
Read the body of the letter. Look for what it asks you to do, any date it gives you to do it by, and the contact information printed on it. If it responds to something you sent, match it against your own copy of what you sent.
If the letter names a deadline, treat that date as real even though the letter is informal-looking. If it asks for nothing and simply explains something — for example, that a document you sent was returned — you may not need to do anything at all.
If you cannot tell what it is about, call the number printed on the letter itself, or check your IRS Online Account for a related notice. If the IRS's requested action involves money or a legal right, get help from a tax professional before responding.
What the letter actually is
The Internal Revenue Manual describes Letter 3064C as a "special IDRS letter," used "when a short narrative reply specifically tailored to the individual taxpayer is needed." It was formerly called a C-NOTE. Using it is an option determined by local management, and the manual says it may be used where an examiner's handwriting would make a handwritten Quick Note (Form 5260) inappropriate.
The point is that the IRS writes it, sentence by sentence, for one taxpayer. Nearly every other IRS letter — a CP504, an LT11, a CP2000 — has fixed text, a fixed subject, and a fixed set of consequences. Letter 3064C has none of those. It is closer to a personal note typed on IRS letterhead than to a form.
Why the IRS uses it
The IRM instructs employees to use a standard IDRS C letter whenever one exists, and not to use Letter 3064C if another appropriate C or SC letter is available. It is what is left when no pre-written letter fits. The manual's own examples of when a brief tailored message suffices include answering a simple inquiry, returning documents with a short explanation, acknowledging receipt of forms or data, sending an interim reply or an apology for delay, and asking for a missing Social Security number.
That range is why the code is so uninformative. The same letter format carries good news, bad news, and neither.
What Letter 3064C gets confused with
Because it arrives on IRS letterhead with a number, it is easy to treat Letter 3064C as one of the standard notices. It is not a CP or LT notice, which have fixed text and fixed consequences. It is not a Notice of Deficiency or a final notice of intent to levy, so it does not by itself start a petition or hearing deadline. And it is not proof that a problem exists: an examiner may send one simply to return a document or acknowledge that something arrived.
Uses the IRM documents
The IRM names Letter 3064C in specific procedures, which gives a sense of the range. When a third party supplies a new address and the IRS cannot yet verify it, the individual-return-delinquency procedures direct employees to send "Letter 3064-C or other appropriate letter" to the prison address and include Form 8822, Change of Address. The corporate-return processing procedures direct employees to return a Pro Forma return that arrived without an accompanying Form 1120-series return using a letter such as 3064C, with language along the lines of "The form appears to have been sent to us in error. Please keep it for your tax records."
These are two examples, not a complete list. The IRS can use the letter for anything a reviewer decides needs a short personal reply, so a use not listed here is entirely possible.
How to read one
Start with three questions: what is the letter responding to, what does it ask of you, and by when. A 3064C that replies to a document you sent is usually a status update. One that asks for information or a signature is a request with a practical deadline, whether or not the letter labels it one.
Then check whether it connects to a standard notice you already hold. If you have received a formal notice with statutory deadlines — for example a final notice of intent to levy — those deadlines run from that notice, not from a later informal reply. Do not assume a 3064C extends, satisfies, or cancels anything unless it says so in plain words. The IRS Notice Library is the place to look up the standard notice a 3064C might be answering.
Finally, keep the envelope and the letter together, note the date received, and answer using the contact method the letter itself specifies. If you are unsure whether the letter is genuine, contact the IRS through a number you find independently rather than one printed only on the letter, or sign in to your Online Account, and see the notice lookup for related codes.
Where this comes from
The description of the letter comes from IRM 2.11.1.2.4 and IRM 21.3.3.4.21, the manual's rules for special IDRS letters and Quick Notes. The two documented uses come from IRM 5.19.2 and IRM 3.12.16. The IRS publishes no plain-language page for Letter 3064C, because there is no single content to describe.
Common Questions
What does Letter 3064C mean?
By itself, nothing specific. It is the IRS's "special IDRS letter": an employee writes a short custom reply for one taxpayer when no standard letter fits. The meaning is in the body of your own letter.
Does Letter 3064C have a deadline?
Only if the letter states one. There is no built-in deadline attached to the code, so read the body for any date or requested action.
Is Letter 3064C the same as a CP or LT notice?
No. CP and LT notices have fixed text and fixed consequences. Letter 3064C has no fixed content — the IRS manual says to use a standard C or SC letter instead whenever one fits.