The short answer
ATTN is short for “attention.” An ATTN line routes a letter addressed to a company or agency to a specific person, department, or job title inside it. On the envelope, USPS Publication 28 puts the attention line above the company name, with the street address and the city, state, and ZIP Code below, as in ATTN DANA REYES, then NORTHFIELD SUPPLY CO, then the street line and the last line.
What does ATTN mean?
ATTN is the abbreviation of “attention,” and on mail it means “for the attention of.” It tells whoever opens or sorts mail at an organization which person, department, or role should get the letter. USPS calls it the attention line, and its Business Mail 101 guide labels the top line of a delivery address “Name or attention line.”
The key idea is that the organization, not the person, is the addressee. The attention line is a routing note for the company’s mailroom or front desk. You’ll see the short form on official addresses too: the IRS tells applicants to mail Form SS-4 to “Internal Revenue Service, Attn: EIN Operation” in Cincinnati.
You may see it written ATTN, Attn:, or spelled out as Attention:. All three mean the same thing. On an envelope, USPS prefers capital letters and lets you drop punctuation, so ATTN without a colon matches its style; inside a letter, the writing guides cited below spell out “Attention”.
Where does the attention line go on an envelope?
Put it at the top of the address block, above the company name. Publication 28, USPS’s addressing standard, says it in one sentence in section 214: the attention line is placed above the recipient line, that is, above the name of the firm the mailpiece is directed to.
The reason is how sorting machines read. USPS explains that its automated equipment reads addresses from the bottom up: it looks first for the city, state, and ZIP Code, then for the delivery address line just above it. Anything below the delivery address line, including an attention line, a logo, or a slogan, can confuse the machines and misdirect the letter. Business Mail 101 puts it plainly: always put the attention line on top, never below the city and state or in the bottom corner of the envelope.
Publication 28 adds that the company name, the delivery address line, and the city, state, and ZIP+4 line must be the last three lines of a business address. So an ATTN line can never sit between the company name and the street address. Everything else, including the attention line, goes above those three lines.
| Line | What goes on it | Required by USPS? |
|---|---|---|
| Attention line | ATTN and a person’s name, job title, or department | No: optional for the mailer |
| Department (optional) | A group, department, or division name | No: optional for the mailer |
| Company name | The business or agency the letter is addressed to | Yes: one of the last three lines |
| Delivery address line | Street number and name with any suite number, or a PO Box | Yes: one of the last three lines |
| Last line | City, two-letter state, and ZIP Code or ZIP+4 | Yes: always the bottom line |
How do you address a letter to a company?
Start with the company’s exact mailing address, ideally from its website, an invoice, or a letter it sent you, then build the block from the top down. Our envelope guide covers where the address, return address, and stamp go on the envelope; these steps cover only the recipient lines for a business.
- Attention line: ATTN followed by the person’s name, such as ATTN DANA REYES. If you don’t have a name, use a job title or department instead.
- Company line: the business’s name as it appears on its own mail, such as NORTHFIELD SUPPLY CO.
- Delivery address line: the street number and name with any suite number at the end, such as 400 COMMERCE DR STE 120, or the company’s PO Box.
- Last line: city, two-letter state abbreviation, and ZIP Code, with the ZIP+4 if the company publishes one.
How do you address a letter to a department or job title?
When you don’t know who should read the letter, direct it to the role or team: ATTN ACCOUNTS PAYABLE, ATTN HUMAN RESOURCES, or ATTN HIRING MANAGER. Walton College’s business-letter guide recommends exactly this when you aren’t certain of the person’s name, while also advising you to try to find the name first.
Publication 28’s full sample business address has separate optional lines for an individual title, a functional title such as DESIGN ENGINEERING MANAGER, and a group, department, or division name, all stacked above the company name. USPS also notes that the attention line with a person’s name, or a functional title, may be critical for delivery inside the firm, but that using both may not be necessary.
Keep the block short. Publication 28 says that generally only five lines of address information are suitable for automated processing when a letter isn’t barcoded. For most letters that means one attention line, an optional department line, and the three required lines. Some large organizations also assign mail stop codes; Publication 28’s sample shows one (MSC and a code) at the very top, above the attention line, so use one only if the organization gives it to you.
ATTN address examples
The first five rows use fictional names and placeholder ZIP Codes; replace every part with the organization’s real details. The last row is USPS’s own sample from Publication 28, which uses more lines than a typical letter needs. A slash separates the lines, which read top to bottom on the envelope.
| Situation | Address lines, top to bottom | Notes |
|---|---|---|
| Named person at a company | ATTN DANA REYES / NORTHFIELD SUPPLY CO / 400 COMMERCE DR STE 120 / ANYTOWN MN 12345-6789 | The standard four-line business address |
| Department | ATTN ACCOUNTS PAYABLE / NORTHFIELD SUPPLY CO / 400 COMMERCE DR STE 120 / ANYTOWN MN 12345-6789 | Use when any member of a team can handle it |
| Job title, name unknown | ATTN HIRING MANAGER / LAKEVIEW COMMUNITY CLINIC / 88 ELM ST / ANYTOWN WI 12345 | Try to find the person’s name first |
| Person in a department | ATTN DANA REYES / CUSTOMER RELATIONS / NORTHFIELD SUPPLY CO / 400 COMMERCE DR STE 120 / ANYTOWN MN 12345-6789 | Five lines, the practical maximum |
| Company PO Box | ATTN CLAIMS DEPARTMENT / HARBOR MUTUAL INSURANCE / PO BOX 4400 / ANYTOWN TX 12345-4400 | The PO Box replaces the street line |
| USPS’s full sample (Publication 28) | MSC 4567ABCD / MS MILDRED DOE / PROFESSIONAL ENGINEER / DESIGN ENGINEERING MANAGER / BRAKE CONTROL DIVISION / BIG BUSINESS INCORPORATED / 12 E BUSINESS LN STE 209 / KRYTON TN 38188-0002 | Shows every optional line; USPS says few addresses use all of them |
Where does ATTN go inside a letter?
Inside the letter, the convention is different from the envelope. Walton College lists the attention line after the inside address, followed by any subject or reference line and then the salutation, and gives “Attention: Department of Accounting” as its example. Austin Community College’s library guide shows an attention line such as “Attention Claims Manager” used where the salutation would go when you’re writing to a manager you don’t know by name or to a department.
Don’t confuse the attention line with the subject line. ATTN says who should read the letter; a subject line says what it’s about (“Subject: Invoices”), and a reference line points to a number the reader will recognize (“RE: Invoice 1234”), per Walton College. A letter to a company can use all three.
If you use a salutation as well, match it to the attention line. MIT’s Mayfield Handbook suggests naming the department when you don’t know the recipient, as in “Dear Technical Support:”, and advises against “Dear Sir or Madam:”. Our business letter guide covers the inside address, spacing, and closing in full.
ATTN vs. c/o: what’s the difference?
Use ATTN when the organization is the addressee and you want the letter routed to someone inside it. Use C/O (“care of”) when a person is the addressee and the household or business is only receiving the letter for them, such as a guest at a friend’s home or a client reached through a law office. The line order differs too: ATTN goes above the company name, while C/O goes below the recipient’s name. Our c/o guide has the full format and examples.
| Question | ATTN | C/O |
|---|---|---|
| Who the letter is for | The organization, routed to a person, team, or role | The named person, receiving mail through someone else |
| First line | ATTN DANA REYES | JAMIE CHEN |
| Second line | NORTHFIELD SUPPLY CO | C/O NORTHFIELD SUPPLY CO |
| Typical use | An employee or department at their own workplace | A guest, client, or anyone without their own mail at that address |
Does an ATTN line mean only that person can open the letter?
No. The Domestic Mail Manual says that all mail addressed to an organization, or to an individual by name or title at the organization’s address, is delivered to the organization. That includes mail for former employees, officials, and contractors. If there’s a dispute over where such mail should go, it is delivered under the order of the organization’s president or equivalent official.
In practice, the attention line is a request to the organization’s mail handlers, not a lock. Whether a mailroom opens, scans, or forwards letters is the organization’s own policy. If a letter is truly personal, send it to the person’s own address instead of their workplace, and if you must prove a business received a notice, see our Certified Mail guide; check with whoever sets the requirement, because notice rules vary by state and by contract, and this article isn’t legal advice.
Common ATTN mistakes
Most addressing problems with attention lines come from putting the line in the wrong place or crowding the address block. These are the ones USPS guidance warns about, plus one habit that trips up letters to agencies.
- Putting ATTN at the bottom. An attention line under the city, state, and ZIP Code, or in the bottom corner of the envelope, can confuse the machines that read the address from the bottom up.
- Putting ATTN between the company and the street. The company name, delivery address line, and city, state, and ZIP Code line must be the last three lines.
- Stacking too many lines. A name, a title, a functional title, and a department all add up; USPS says generally only five lines are suitable for automated processing without a barcode, and using both a name and a functional title may not be necessary.
- Using C/O for an employee. C/O means the person doesn’t have their own mail at that address; ATTN, or simply the person’s name above the company name, fits someone at their own workplace.
- Rewriting an address the organization publishes. Some agencies print their own attention line in a set spot, such as the IRS’s “Attn: EIN Operation,” which appears below “Internal Revenue Service.” Copy a published address exactly as given rather than reordering it.
- Leaving the company name off. Without it, a mailroom sees only a person’s name and a street address, and the company line is one of the lines USPS requires for a business address.
How do you add an attention line when you mail through IRIS?
IRIS’s letter form has a Name or company field (up to 40 characters), a Street address field, an optional Apt, suite, unit field, City, a two-letter State, and ZIP. There’s no separate attention line or company line, so you have two options. If both fit within 40 characters, put them on one line, company first, such as NORTHFIELD SUPPLY ATTN D REYES. Otherwise, enter the company name alone and put the attention line in the inside address of your PDF, where the person opening the letter will see it. Don’t put ATTN in the Apt, suite, unit field, which is meant for a suite or unit number.
IRIS is an independent print-and-mail service, not USPS. It prints the US Letter-size PDF you upload and mails it by USPS First-Class Mail to a US address, and you review the document, addresses, options, and total before paying. A letter costs $3.00 plus $0.20 per black-and-white page or $0.40 per color page, so a one-page black-and-white letter is $3.20; Certified Mail adds $6.95. IRIS can’t enclose physical items such as checks or original documents, and order status isn’t proof of delivery.
Sources & further reading
Product details checked against the IRIS API contract when this article was published. Platform references can change; consult the linked documentation when implementing.
- USPS Publication 28, 214: Attention line
- USPS Publication 28, 33: Business address data elements
- USPS Publication 28, 341: Sample business address format
- USPS Publication 28, 343: Address line removal
- USPS Publication 28, 222: Punctuation
- USPS Business Mail 101: Delivery address
- USPS Domestic Mail Manual 508: Recipient services
- IRS: Where to file Form SS-4
- University of Arkansas Walton College: Formatting the Business Letter (PDF)
- Austin Community College Library: Parts of a business letter
- MIT Mayfield Handbook: Letters
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