AMA citation style is the numbered citation system published in the AMA Manual of Style by the American Medical Association, and it is the standard format for medical, nursing, and health science papers. Works are marked in the text with a small superscript number, and each number points to a full entry at the end of the paper, listed in the order they first appear. This guide walks through the formatting rules, in-text citation mechanics, and citation patterns for the material types students cite most often, with worked examples for each.
What Is AMA Citation Style?
AMA citation style refers to the citation and formatting rules published in the AMA Manual of Style, now in its 11th edition. It is a numbered citation system, which means sources are tracked by number rather than by author name and year, the way APA and MLA track them. AMA style is a close relative of the Vancouver system used across biomedical and scientific publishing, and the two share the same superscript numbering logic and similar reference formatting.
Because AMA style was built for medical journals, it favors compact, information-dense references over long descriptive ones. An entry lists just enough to locate the work: names, title, publication name, year, volume, issue, and page range for a journal article, for instance, with no extra commentary.
AMA In-Text Citations: The Superscript Numbering System
AMA in-text citations use superscript Arabic numerals placed after the claim they support, not author names or years. The first work cited in a paper is numbered 1, the second new one is numbered 2, and so on. If the same work is cited again later, it reuses its original number rather than getting a new one.
Superscript numbers are placed outside periods and commas, but inside colons and semicolons. When two numbers are cited together, they are separated by a comma with no space. A run of three or more consecutive numbers is shortened with a hyphen.
Correct: Regular exercise reduces cardiovascular risk.1 Multiple studies confirm this finding.2,3
Incorrect: Regular exercise reduces cardiovascular risk (1). Multiple studies confirm this finding [2, 3].
How to Format an AMA Reference List
The AMA reference list appears at the end of the paper under the heading “References.” Unlike APA or MLA, entries are numbered in the order each work first appears in the text, not alphabetized by name. Each entry follows the same basic order:
- Names and initials of everyone credited with the work
- Title of the article, page, or book
- Publication name, year, and volume or edition data
- A locator, such as a page range, section, or DOI
Names are listed as last name followed by initials, with no comma between them. Up to six are listed by name before switching to “et al.” for larger groups.
Citing Multiple Contributors and Organizations in AMA Style
When a work has two to six contributors, list each person’s last name and initials in the entry, separated by commas, in the order they appear on the original publication. This rule applies whether the authors are individual researchers or a mixed group of authors and editors. When there are more than six, list only the first six names and add “et al.” after the sixth, following the standard the National Library of Medicine uses for indexing biomedical literature.
Organizations, such as a government agency or a professional association, can also stand in as the credited party. The full organization name is used the same way a person’s name would be, and no individual staff members are named unless the work itself credits a specific person.
AMA Reference List Examples by Source Type
The exact citation pattern changes slightly by material type. The table below covers the formats used most often in coursework and research papers, drawn from the formatting rules in the AMA Manual of Style.
| Material Type | AMA Citation Format & Example |
|---|---|
| Journal article | Author AA, Author BB. Title of article. Journal Name. Year;Volume(Issue):Pages. Chen L, Patel R. Statin use and long-term cardiovascular outcomes. JAMA. 2023;329(4):310-318. |
| Book | Author AA. Title of Book. Edition. Publisher; Year. Harrison TM. Principles of Internal Medicine. 21st ed. McGraw-Hill; 2022. |
| Website | Author/Organization. Title of page. Site Name. Published date. Updated date. Accessed date. URL Centers for Disease Control and Prevention. Heart disease facts. CDC. Published May 15, 2023. Accessed September 18, 2026. https://www.cdc.gov/heartdisease/facts.htm |
| Newspaper article | Author AA. Title of article. Newspaper Name. Published date:Page. Diaz S. New vaccine trial shows early promise. New York Times. March 3, 2024:A12. |
| No named author | Title of work. Publisher; Year. Clinical guidelines for diabetes management. American Diabetes Association; 2024. |
For material types with their own citation quirks, such as journal articles behind a paywall or an online article without page numbers, the guides for how to cite journals and how to cite an article walk through the edge cases in more depth.
Citing a book or a website comes up just as often in a health sciences paper. The how to cite a book and how to cite a website guides cover multi-edition books, edited volumes, and pages with no visible publish date, all of which need small adjustments to the base AMA format shown above.
Worked Example: A Full AMA Citation Walkthrough
Here is how the pieces fit together in a real paragraph, moving from the in-text superscript numbers to their matching entries.
In the paper: Adherence to a Mediterranean diet is associated with a measurable drop in cardiovascular events.1 This effect held across age groups in a large European cohort,2 and similar results have since been replicated in North American populations.1,3
Because work 1 was cited first, it is numbered 1 everywhere it reappears, including its second mention alongside work 3. The matching set of entries, numbered in that same first-appearance order, would read:
- Chen L, Patel R. Statin use and long-term cardiovascular outcomes. JAMA. 2023;329(4):310-318.
- Moreno-Diaz A, Fontaine J. Mediterranean diet adherence in a European cohort. Eur J Prev Cardiol. 2022;29(11):1502-1510.
- Whitfield K, Oyelaran T. Replicating cardiovascular diet outcomes in North America. Am J Cardiol. 2024;183:45-52.
Notice that entry 1 is not repeated as a new number when it is cited again alongside entry 3. This is the detail that trips up most first-time AMA writers, and it is worth double-checking before submitting a paper. Citing a newspaper feature or a policy brief follows the same numbering logic, with only the format changing. The how to cite a newspaper article guide has worked examples for that material type specifically.
Common AMA Formatting Mistakes to Avoid
| Mistake | Why It’s Wrong and How to Fix It |
|---|---|
| Citing with author-year instead of numbers | AMA is a numbered system, not author-date. Replace “(Smith, 2023)” with a superscript number tied to a numbered entry. |
| Sorting entries alphabetically | AMA entries are ordered by first appearance in the text, not alphabetically by last name. |
| Putting the superscript number before punctuation | Superscript numbers go after periods and commas, so place the number immediately following the punctuation mark. |
| Writing names as “First Last” | AMA lists names as last name followed by initials with no comma, for example “Chen L” rather than “Lisa Chen.” |
| Listing every contributor for large studies | Once a work has more than six contributors, list the first six and add “et al.” for the rest. |
AMA Style vs. Other Citation Styles
AMA style differs from APA and MLA in one fundamental way: it numbers sources instead of citing names in the text. Writers moving between disciplines often need to switch systems entirely rather than just adjusting formatting details. A biology paper for a health sciences course might require AMA, while a psychology paper for the same student requires APA’s name-date system.
| Style | In-Text Format | Reference List Order | Typical Field |
|---|---|---|---|
| AMA | Superscript number | By first appearance | Medicine, health science |
| Vancouver | Number in brackets or superscript | By first appearance | Biomedical, scientific research |
| APA | (Name, Year) | Alphabetical | Psychology, social science |
| MLA | (Name Page) | Alphabetical | Humanities, literature |
AMA and Vancouver style are close enough in their underlying data structure that they are sometimes used interchangeably in journal submission guidelines, though individual journals may specify small variations on top of the base Vancouver rules. For a broader comparison across citation systems, including APA and MLA, the citation styles guide breaks down when each format applies.
Frequently Asked Questions About AMA Citation Style
What is the difference between AMA and APA citation style?
AMA uses superscript numbers tied to a numbered citation list ordered by first appearance in the text, while APA uses author-date citations like (Smith, 2023) with an alphabetized bibliography. The two styles also format their entries differently, with AMA favoring compact, abbreviated publication details.
Do AMA in-text citations include author names?
No. AMA in-text citations use only a superscript number. The name appears in the full citation list entry at the end of the paper, not in the body text next to the number.
How do you cite a source with no listed author in AMA style?
When no individual is named, start the entry with the title of the work or the name of the sponsoring organization in place of a personal name, then continue with the rest of the standard format. Databases and library catalog records often list the underlying data source in place of a personal name too.
Is AMA style the same as Vancouver style?
They are closely related but not identical. AMA style is a specific implementation of the broader Vancouver numbered-citation system, adapted by the American Medical Association with its own formatting rules for the AMA Manual of Style. Some journals that say they use “Vancouver style” apply small variations on the base rules that differ from AMA’s exact requirements.
What edition of the AMA Manual of Style should I use?
Use the current 11th edition unless an instructor or journal specifically requests an older edition. The 11th edition is the version referenced throughout this guide.
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Terry is a Chicago-based writer and editor who creates practical, student-friendly guides on essay writing, research, and citation styles (APA, MLA, and Chicago). He’s spent 15+ years editing educational content and building clear examples that help readers apply rules without guessing. When he’s not revising drafts, he’s usually turning messy notes into clean outlines and hunting down the one detail everyone skips.