Athletics at the 1975 Pan American Games – Women's 400 metres

{{Infobox Pan American Games event

|event = Women's 400 metres

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|win_label = Winning time

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{{Athletics at the 1975 Pan American Games}}

The women's 400 metres event at the 1975 Pan American Games was held in Mexico City on 17 and 18 October.{{cite web|url=http://trackfield.brinkster.net/Tournaments.asp?TourCode=P&Year=1975&Gender=W&TF=T&P=F|website=trackfield.brinkster.net|title=Track and Field Statistics |accessdate=29 November 2019}}[http://atfs.org/wp-content/uploads/Pan-Am-Games-1975.pdf Full results]