How to Cite Something Inside a Footnote in LaTeX

Placing a \\cite inside a \\footnote is common in humanities writing, but can cause subtle issues depending on your citation package.

The basic approach (works in most cases)

This claim requires evidence.\\footnote{See \\cite{smith2024} for a full discussion.}

% With natbib:
This claim\\footnote{See \\citep{smith2024} for details.}

The problem: nested fragile commands

Some citation commands are "fragile" and break inside footnotes or captions. If you get errors, protect the command:

\\footnote{See \\protect\\cite{smith2024}.}

biblatex's built-in footnote citations

biblatex has dedicated footnote citation styles:

\\usepackage[style=verbose]{biblatex}

% \\footcite produces a footnote automatically
This is a claim.\\footcite{smith2024}
% Output: This is a claim.¹
% Footnote: ¹ Smith, "Title," Journal, 2024.

Other footnote commands in biblatex

Command	Description
\\footcite{key}	Full citation in footnote
\\footcitetext{key}	Footnote text only (no marker)
\\footfullcite{key}	Full bibliographic entry in footnote
\\autocite{key}	Adapts to style (footnote in verbose styles)

Best practice

• Humanities/law: Use biblatex with style=verbose and \\footcite
• STEM: Use \\cite inside \\footnote — it works fine with numeric styles
• If in doubt: Use \\autocite from biblatex — it automatically picks the right format

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