To cite an IRS publication in Bluebook format, use: I.R.S., Pub. No. 501, Dependents, Standard Deduction, and Filing Information (2025). In APA 7th Edition, the same document becomes: U.S. Internal Revenue Service. (2025). Your federal income tax: For individuals (Publication 17). https://www.irs.gov/pub/irs-pdf/p17.pdf. Those two patterns cover most general IRS publications and forms. If what you’re actually citing is a section of the tax code, a Treasury Regulation, or a Revenue Ruling, the format changes, and using the publication pattern for those documents will misrepresent what you’re citing.
Information to Pull From the Document First
Before formatting anything, collect these pieces from the document itself: the issuing agency (Internal Revenue Service or Department of the Treasury), the title, the publication or form number, the revision date, and the URL if you accessed it online.
The revision date is the piece people miss. On publications like Publication 501 or Publication 17, the IRS prints the revision date in the bottom margin of the first page, usually as a year or a month-year combination. On forms, look at the bottom right margin. Revised documents may show “Rev. 2025” or “Rev. 01-2025” instead of a bare year. Use whatever the document says.
Bluebook Format for IRS Publications
General IRS publications and forms are administrative materials under Bluebook Rule 14, and Table T1.2 gives the agency-specific instructions for the Department of the Treasury.
A full Bluebook citation has four components in order: the agency name, the document title with its publication number, a parenthetical with the revision date, and (if online) the URL. In law review footnotes, the agency name appears in large and small capitals. The finished citation:
I.R.S., Pub. No. 501, Dependents, Standard Deduction, and Filing Information (2025), https://www.irs.gov/pub/irs-pdf/p501.pdf.
A few details to get right. “I.R.S.” takes periods after each letter. The publication number uses the abbreviated “Pub. No.” form. The title is not italicized. To point a reader to a specific page, add a pinpoint after the title: “Pub. No. 501, at 12.” Court documents and practitioner briefs use ordinary roman type instead of the small caps used in academic writing.
APA Format for IRS Publications
APA 7th Edition treats IRS documents as government reports with a group author. A reference list entry has the organizational author, the year in parentheses, the italicized title in sentence case, and the retrieval URL. Because the IRS is both author and publisher, you omit the publisher name to avoid repeating it.
A reference list entry:
U.S. Internal Revenue Service. (2025). Your federal income tax: For individuals (Publication 17). https://www.irs.gov/pub/irs-pdf/p17.pdf
The publication number sits in parentheses after the title and is not italicized. The title uses sentence case: only the first word, proper nouns, and the first word after a colon are capitalized.
In-Text Citations
APA lets you abbreviate “Internal Revenue Service” to “IRS” after the first mention, provided the abbreviation appears at least three times in the paper. How you introduce it depends on the form of your first citation.
If you name the agency in your sentence, put the abbreviation and year together in parentheses:
The U.S. Internal Revenue Service (IRS, 2025) explains that most taxpayers can claim the standard deduction.
If the whole citation is parenthetical, use square brackets for the abbreviation:
(U.S. Internal Revenue Service [IRS], 2025)
Every citation after that can read “(IRS, 2025)” or “The IRS (2025) states…” In the reference list itself, always spell the full agency name out, regardless of how often you abbreviated in the text.
When the Document Isn’t a “Publication”
The publication format above is for informational documents like Publication 17 or Publication 501. Several other IRS-related documents you might be citing follow different rules, and using the publication pattern for them is a common error.
The Internal Revenue Code
The Internal Revenue Code is Title 26 of the United States Code, but the Bluebook treats it specially. Under Rule 12.9, cite it as “I.R.C.” rather than “26 U.S.C.” Using the standard U.S. Code format for tax provisions marks the writer as unfamiliar with the field.
The basic form:
I.R.C. § 61(a).
Include a parenthetical year only when the code edition matters, such as when you’re citing a provision as it read before an amendment. For current provisions the year is usually omitted. In shortened form, after a full citation has appeared, “§ 61(a)” is enough.
Treasury Regulations
Treasury Regulations are codified in Title 26 of the Code of Federal Regulations, but Table T1.2 tells you not to cite them as “26 C.F.R.” Use “Treas. Reg.” with the section number:
Treas. Reg. § 1.61-1 (2003).
The parenthetical year should be when the regulation was promulgated or last amended. Temporary regulations add a “T” after the section number (Treas. Reg. § 1.61-1T). Proposed regulations take “Prop.” in front: Prop. Treas. Reg. § 1.61-1.
Revenue Rulings and Revenue Procedures
Revenue Rulings are the IRS’s official interpretations applying the code to specific facts. Revenue Procedures set out administrative steps taxpayers should follow. Both appear in the Internal Revenue Bulletin and are later collected in the Cumulative Bulletin.
Table T1.2 directs you to cite to the Cumulative Bulletin (C.B.) where available, and to the Internal Revenue Bulletin (I.R.B.) otherwise. The format uses the document’s number followed by the bulletin reference:
- Revenue Ruling: Rev. Rul. 2001-68, 2001-2 C.B. 159.
- Revenue Procedure: Rev. Proc. 2015-13, 2015-5 I.R.B. 419.
The number tells the reader the year and sequence: “2001-68” is the 68th ruling issued in 2001. Use hyphens, not en-dashes, in the ruling number.
Private Letter Rulings
Private letter rulings are IRS responses to individual taxpayers about their specific situations. The statute states that a written determination generally “may not be used or cited as precedent.”1Office of the Law Revision Counsel. 26 U.S. Code 6110 – Public Inspection of Written Determinations They still turn up in tax research for their persuasive value, and the Bluebook citation uses the ruling number:
I.R.S. Priv. Ltr. Rul. 202401001 (Jan. 5, 2024).
A related point worth knowing if you’re citing IRS material to support a tax position: the regulation defining “substantial authority” for penalty purposes lists which authorities count, and general publications and private letter rulings issued to other taxpayers are not on the list, while Treasury Regulations and Revenue Rulings are.2eCFR. 26 CFR 1.6662-4 – Substantial Understatement of Income Tax That affects which document you should be citing in the first place.
Quick Reference
The core patterns for the documents you’re most likely to encounter:
- IRS Publication (Bluebook): I.R.S., Pub. No. 501, Dependents, Standard Deduction, and Filing Information (2025).
- IRS Publication (APA): U.S. Internal Revenue Service. (2025). Dependents, standard deduction, and filing information (Publication 501). https://www.irs.gov/pub/irs-pdf/p501.pdf
- Internal Revenue Code (Bluebook): I.R.C. § 61(a).
- Treasury Regulation (Bluebook): Treas. Reg. § 1.61-1 (2003).
- Revenue Ruling (Bluebook): Rev. Rul. 2001-68, 2001-2 C.B. 159.
- Private Letter Ruling (Bluebook): I.R.S. Priv. Ltr. Rul. 202401001 (Jan. 5, 2024).
Identify the document type before you format the citation. A publication, a regulation, and a ruling each follow different rules, and matching the format to the document is the habit that prevents the most common errors in tax citation.