ATTN Line Addressing Guide: How to Use Attention Lines Correctly

What Is an ATTN Line?

ATTN stands for "Attention" and is used in mail addressing to direct a letter or package to a specific person within an organization, business, or household. The attention line tells mail handlers that while the mail is addressed to a company or location, it should be delivered to a particular individual.

Using an attention line is especially important when sending mail to large organizations where general mail might be opened by administrative staff or routed through a mailroom. The ATTN line helps ensure your correspondence reaches the intended recipient. Note that ATTN is not required by USPS—automated mail sorting relies primarily on the city, state, and ZIP code lines—but it serves as a helpful routing aid for humans in the mailroom or office who handle internal distribution.

Both "ATTN:" and the full word "Attention:" are acceptable formats. The abbreviated "ATTN:" is more common in business correspondence and saves space on the envelope.

When to Use an Attention Line

Attention lines are appropriate in several situations:

• Business correspondence: When sending mail to a specific employee at a company
• Government agencies: When directing mail to a particular department or official
• Legal documents: When ensuring legal notices reach the correct person
• Shared residences: When multiple people live at the same address
• PO Boxes: When a PO Box is shared by multiple individuals or a business
• Apartment buildings: When the recipient's name differs from the name on the mailbox

If you are sending mail to someone at their own home where they are the primary resident, an attention line is typically not necessary. Simply address the envelope to them directly.

Where to Put the ATTN Line on an Envelope

According to USPS addressing standards, the attention line should be placed on the first line of the address block. If you're wondering how to write an attention line on an envelope, here's the standard order:

Key placement rules to follow when addressing your envelope:

• The ATTN line goes above the organization or business name
• Keep all address lines left-aligned
• Use all capital letters for better mail processing (though mixed case is also accepted)
• Do not place the ATTN line below the street address
• Include the colon after ATTN: for clarity

TL;DR: Put ATTN: on the first line, above the business name, and keep the rest of the address in standard USPS format.

ATTN Line Format Examples

Here are sample ATTN line formats you can use as templates when addressing your envelope. Notice that all examples use "ATTN:" on the first line with the rest of the address following standard USPS format.

Business Address with ATTN Line

Government Agency

Shared Residence

PO Box

Using Full "Attention" Word

ATTN vs C/O: What's the Difference?

Many people are unsure whether to write ATTN or C/O on their envelope. While both help direct mail to specific individuals, they serve different purposes:

Use ATTN when: The recipient works at or has an official connection to the organization or address.

Use C/O when: The recipient is temporarily staying with someone, using another person's address for mail, or receiving mail through an agent or representative.

Common Mistakes to Avoid

• Placing ATTN on the wrong line: The attention line should always be the first line of the address block, not buried in the middle or at the end.
• Using ATTN when C/O is appropriate: If someone is staying at another person's home or receiving mail through an agent, use C/O instead of ATTN.
• Omitting the organization name: When using ATTN for business mail, still include the company name on the second line to ensure proper routing. This is especially important for certified mail where accurate delivery is critical.
• Placing ATTN in the return address: The ATTN line belongs only in the recipient's address, not in your return address.
• Using both ATTN and C/O: Choose one or the other based on the situation. Using both is redundant and can cause confusion.
• Forgetting the name after ATTN: The attention line must include the recipient's name or department (e.g., "ATTN: Billing Department").

Frequently Asked Questions