The mixed 4 × 400 metres relay at the 2024 World Athletics U20 Championships will be held at the Estadio Atlético de la VIDENA in Lima, Peru on 27 August 2024.

U20 standing records prior to the 2024 World Athletics U20 Championships were as follows:[1] First 2 of each heat (Q) plus the 2 fastest times (q) qualified for the final.

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