AMA citation style is the referencing system defined by the AMA Manual of Style, published by the American Medical Association. It uses superscript Arabic numerals in the text and a reference list numbered in citation order. It is the house style of JAMA and a large share of medical, nursing, and biomedical journals published in the United States, so any author submitting to those titles needs to know it.
AMA belongs to the same family of numbered styles as Vancouver, and the two are frequently confused. This guide sets out the AMA rules with examples and then draws the contrast explicitly.
In-Text Citations in AMA Style
AMA cites sources with a superscript number placed at the point of citation. The defining detail is placement: in AMA, the superscript numeral goes after commas and periods. For example: The trial reported a significant reduction in mortality.¹ When a clause cites several sources, use commas with no spaces, and a hyphen for ranges: as shown in earlier work.²,⁴,⁷ or in three trials.²⁻⁴
Each source keeps the number it received the first time it appeared. Reusing a source later in the paper means reusing its original number, exactly as in Vancouver. Because the numbering is positional, inserting a citation renumbers the rest of the document, so a reference manager is essential for anything longer than a short letter.