Vancouver referencing is a numbered citation style in which sources are cited in the text with sequential numbers and listed in the reference list in the order they first appear. It is the standard across medicine and the biomedical sciences, and it forms the backbone of the reference format recommended by the International Committee of Medical Journal Editors (ICMJE). If you are preparing a clinical paper, a systematic review, or a thesis in the health sciences, Vancouver is almost certainly the style your target journal expects.
This guide explains how the Vancouver citation system works, gives worked examples for every common source type, and flags the formatting errors that most often come back from copy editors and reviewers.
How the Vancouver Numbering System Works
The defining feature of Vancouver style referencing is that citation order, not author surname, drives everything. The first source you cite becomes reference 1, the second becomes reference 2, and so on. When you cite a source again later in the manuscript, you reuse its original number rather than assigning a new one. This is the opposite of author-date systems such as APA or Harvard, where the reference list is alphabetical and the in-text marker is the author and year.
Because the numbering is tied to position, inserting a new citation midway through a finished draft renumbers everything that follows. This is exactly why experienced authors use a reference manager rather than numbering by hand; our comparison of the best reference managers and the practical Zotero versus Mendeley breakdown both cover tools that automate Vancouver numbering and renumber the whole document when you move a citation.
In-Text Citation Format
The in-text marker is an Arabic numeral. The exact presentation varies by journal, and you should always check the author guidelines, but the three accepted forms are:
- Parentheses: Antibiotic stewardship reduced resistance rates (1).
- Square brackets: Antibiotic stewardship reduced resistance rates [1].
- Superscript: Antibiotic stewardship reduced resistance rates.¹
When you cite more than one source at once, use a hyphen for a continuous range and commas for non-sequential numbers: (2-5) for references two through five, and (2,4,7) for three separate sources. The number is placed after the relevant clause, usually before the period, though some journals place superscript markers after punctuation.