Form I-485 · Part 1, Item 4
I-485 A-Number (Part 1, Item 4): Do You Leave It Blank?
What the Alien Registration Number (A-Number) is, where to find it, how to format it, and why most first-time filers in Part 1, Item 4 have none and leave it blank.
Quick answer
Most first-time marriage-based filers leave the A-Number blank. You only have an Alien Registration Number (A-Number), the number USCIS uses to track a person across immigration records, if USCIS or the immigration courts assigned you one before. If you have never had contact with USCIS or immigration, you have none, and Item 4 stays blank because it is marked "if any."
Summary
Form I-485 Part 1, Item 4 asks "Do you have an Alien Registration Number (A-Number)?" and the A-Number field is marked "if any" because not everyone has one. The A-Number is the Alien Registration Number USCIS uses to track a single person across all of their immigration records: the letter A followed by 7 to 9 digits. The applicant is the immigrant spouse filing this I-485 to get a green card; the petitioner is the U.S. citizen or green card holder sponsoring them on the I-130; the same immigrant spouse is also called the beneficiary on that petition. A spouse seeking a green card for the first time, who has never filed anything with USCIS and was never in immigration court, usually has no A-Number yet. In that case you answer "No" to Item 4 and leave the A-Number boxes blank. The A-Number is not the USCIS Online Account Number (Item 9) and not the case receipt number on a USCIS notice.
| What it asks | Whether you have an Alien Registration Number (A-Number), and if so, the number itself. The field is marked "if any." |
| Most marriage cases | Answer "No" and leave the boxes blank. A spouse filing for the first time, with no prior USCIS or immigration-court contact, usually has no A-Number. |
| When you have one | If USCIS or an immigration court assigned you an A-Number before, for example through a prior application, an Employment Authorization Document (EAD), a prior visa case, or a removal case. |
| Format | The letter A followed by 7 to 9 digits, for example A123456789. Pad shorter numbers with leading zeros to fill the digit boxes. |
| Not the same as | Not your USCIS Online Account Number (Item 9) and not your case receipt number. These are three different numbers. |
Who this page is for
This page covers reading and formatting an A-Number you already have, and confirming you have none. It does not cover what any prior immigration history means for your case. If you have an A-Number from a removal or deportation case, a prior denial, or a prior application you are unsure about, people in that situation often consult a licensed immigration attorney before completing this field.
What Item 4 looks like on the form
This field sits in Part 1 (Information About You). Item 4 asks a Yes or No question and then gives a row of digit boxes preceded by a printed “A-”. Item 5, just below, asks about any other A-Number you have used.
Verbatim · Form I-485, Part 1, Item 4 (edition 01/20/25, page 2)
“Do you have an Alien Registration Number (A-Number)?” “If you answered "Yes," provide your A-Number.”
A-Number (if any)
Verbatim · I-485 Instructions, “How To Complete Form I-485,” Item 2 (edition 01/20/25, page 5)
“If you need extra space to complete any item within this application, use the space provided in Part 14. Additional Information or attach a separate sheet of paper. Type or print your name and Alien Registration Number (A-Number) (if any) at the top of each sheet; indicate the Page Number, Part Number, and Item Number to which your answer refers; and sign and date each sheet.”
Always complete the current edition from uscis.gov/i-485; USCIS rejects outdated editions.
Three numbers people mix up
The A-Number, the USCIS Online Account Number, and the receipt number are three different things. Item 4 wants only the A-Number, and only if you have one.
| Number | What it is | Format example | On the I-485 |
|---|---|---|---|
| A-Number (Alien Registration Number) | The number USCIS uses to track one person across all of their immigration records. Many first-time applicants do not have one yet. | The letter A followed by 7 to 9 digits, for example A123456789 | Part 1, Item 4 (and Item 5 for any other A-Number) · also at the top of every page · leave blank if none |
| USCIS Online Account Number | A number tied to your USCIS online account. You get one only after a prior filing whose receipt number begins with IOE, or after USCIS issues one for an online account. | Usually a 12-digit string | Part 1, Item 9 · leave blank if you have none |
| Receipt number | The case-specific tracking number USCIS prints on the receipt notice (Form I-797) after it accepts a filing. | Three letters then 10 digits, for example IOE0912345678 or MSC2190000000 | Not an I-485 field · it appears on your receipt notice after you file |
Where to find it (and when there is nothing to find)
Work through these in order. If none of them turn up a number, you do not have one, and Item 4 is answered “No.”
Check whether USCIS or immigration ever assigned you a number
You only have an A-Number if USCIS, the immigration courts, or a prior immigration process gave you one. If this I-485 is your household's first interaction with USCIS, you almost certainly have none. A spouse who entered on a tourist or other nonimmigrant visa and never filed anything usually has no A-Number until USCIS opens this case.
Look at prior USCIS notices and decisions
If you ever received a Form I-797 notice or a decision from USCIS on an earlier application, the A-Number is usually printed near the top, often labeled "A#" or "A-Number." Receipt and approval notices are the most common place people find it.
Look at your Employment Authorization Document or prior cards
An Employment Authorization Document (EAD), the work-permit card USCIS issues, prints the A-Number on the front. A prior green card, a prior immigrant visa, or refugee or asylum paperwork also carries it.
Check prior visa and entry documents
Some immigrant visa packets and certain entry records show an A-Number. In some cases it also appears on the Form I-94 arrival record, though many nonimmigrant entries have no A-Number at all. A nonimmigrant visa stamp on its own does not contain an A-Number.
If you have none, answer "No" and leave it blank
Item 4 says "if any." Having no A-Number is normal and correct for most first-time filers. Do not put your USCIS Online Account Number or a receipt number here as a substitute. Answering "No" and leaving the boxes blank is the right answer when no A-Number was ever assigned.
Not sure whether you have one of these numbers?
Our software asks a few plain questions and fills the right fields the right way, keeping your numbers consistent across your whole I-130 and I-485 packet.
Start FreeHow to write the A-Number in the boxes
If you do have an A-Number, the format matters. These four rules cover the digit boxes in Item 4.
It always starts with the letter A
On the form, the boxes are preceded by a printed "A-", so you write only the digits that follow. The A is the prefix, not something you type into the digit boxes.
It is 7 to 9 digits long
Older A-Numbers have 7 or 8 digits; newer ones have 9. The number on your documents is the number you use. Do not add or drop digits to reach a particular length.
Pad shorter numbers with leading zeros
If your A-Number has fewer digits than there are boxes, add zeros at the front so it fills the field. For example, a 7-digit number A1234567 is written 001234567 when the field expects 9 digits. This keeps it consistent with how USCIS stores it.
Use the exact same A-Number everywhere
Whatever A-Number you enter in Item 4 must match the one at the top of every page of the I-485 and the one on your other forms and evidence. A mismatch between pages is a common, avoidable error.
What USCIS does with the A-Number
USCIS uses the A-Number to match this I-485 to any immigration file it already keeps on you, so the adjudicator reviews your full history in one place rather than treating you as a brand-new person. It is a recordkeeping identifier, not an eligibility or status field. Because most first-time applicants have never been assigned one, the field is optional and marked "if any." Answering "No" when you have no A-Number does not slow your case. What causes problems is entering the wrong number, such as a USCIS Online Account Number or a receipt number, since those identify different things, or writing a number that does not match the A-Number on your other documents.
Common mistakes
These are the ones that show up most often on this field.
- 1
Entering a USCIS Online Account Number in the A-Number field
The USCIS Online Account Number is a separate account identifier that goes in Part 1, Item 9, not in Item 4. It is a longer numeric string and is not preceded by an A. Mixing the two is the most common error on this field.
- 2
Entering a case receipt number
The receipt number on a Form I-797 notice (three letters then 10 digits) tracks one specific case. It is not your A-Number. If your only number starts with three letters like IOE or MSC, it is a receipt number, not an A-Number.
- 3
Inventing a number because the boxes are there
The field is marked "if any." If USCIS never assigned you an A-Number, there is nothing to enter. A spouse filing for the first time should answer "No" and leave the boxes blank rather than guess or copy a number from somewhere else.
- 4
Skipping Item 5 when you have had more than one A-Number
Item 5 asks whether you have ever used or been assigned any other A-Number. If a prior process gave you a second A-Number, list it in Item 5 so USCIS can connect every file. Leaving Item 5 at "No" when a second number exists hides part of your record.
- 5
Using a number that does not match your documents
Read the A-Number directly off your prior USCIS notice, EAD, or prior card rather than from memory. A digit transposed or a different A-Number than the one USCIS has on file forces the adjudicator to reconcile records and can delay the case.
Related guides
Form and pathway context
Related questions
Frequently asked questions
I am a spouse filing my first green card application. Do I have an A-Number?
Probably not. You only have an A-Number if USCIS or an immigration court assigned you one before, for example through a prior application, an Employment Authorization Document, a prior visa case, or a removal case. If this I-485 is your first contact with USCIS, answer "No" to Item 4 and leave the A-Number boxes blank.
Is the A-Number the same as my USCIS Online Account Number?
No. The A-Number (Alien Registration Number) is how USCIS tracks a person across their records and goes in Part 1, Item 4. The USCIS Online Account Number is an account identifier and goes in Item 9. They are different numbers and look different: the A-Number starts with the letter A, the online account number does not.
Is it the same as the receipt number on my notices?
No. The receipt number tracks one specific case and is printed on a Form I-797 notice as three letters plus 10 digits. The A-Number is the letter A followed by 7 to 9 digits and identifies you, not a single case.
Where do I find my A-Number if I do have one?
Look at prior USCIS notices or decisions (usually near the top, labeled A# or A-Number), an Employment Authorization Document or prior green card (printed on the front), or prior immigrant visa and immigration paperwork. In some cases it also appears on a Form I-94, though many nonimmigrant entries have none.
My A-Number has only 8 digits but the form has more boxes. What do I write?
Add leading zeros at the front so the number fills the boxes. An 8-digit number A12345678 is written 012345678 when the field expects 9 digits. Use the exact same A-Number at the top of every page and on your other forms.
Will answering "No" to Item 4 cause a problem?
No. The field is marked "if any." Answering "No" and leaving the boxes blank is correct when USCIS never assigned you an A-Number. Entering the wrong number, like a USCIS Online Account Number or a receipt number, is more likely to cause confusion than a truthful "No."
Key takeaways
- ✓
Item 4 is marked "if any." Most first-time marriage-based filers answer "No" and leave the A-Number boxes blank.
- ✓
You only have an A-Number if USCIS or an immigration court assigned you one before, for example through a prior application, an EAD, a prior visa, or a removal case.
- ✓
The format is the letter A followed by 7 to 9 digits (for example A123456789); pad shorter numbers with leading zeros to fill the boxes.
- ✓
It is not your USCIS Online Account Number (Item 9) and not your case receipt number (on a Form I-797 notice).
- ✓
Find it on a prior USCIS notice, an Employment Authorization Document, a prior green card, or prior visa and immigration documents. Use the same A-Number on every page.
This page is for educational purposes only and is not legal advice. Green Card Genius is self-help immigration software, not a law firm, and does not provide legal representation. Immigration law and USCIS policy change frequently. For advice on a specific case, consult a licensed immigration attorney. Form I-485, edition 01/20/25. Last verified May 2026.
Continue reading
- 01Form I-485: Application to Adjust Status (2026 Guide)
- 02I-485 USCIS Online Account Number (Part 1, Item 9): Leave It Blank? (2026)
- 03I-485 Filing Category (Part 2): Which Box a Spouse Checks (2026)
- 04Marriage Green Card by Country: Country-Specific Guides (2026)
- 05Marriage Green Card Document Checklist (2026)
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