The mixed 4 × 400 metres relay at the 2019 IAAF World Relays was held at the Nissan Stadium on 11 and 12 May.

Records Prior to the competition, the records were as follows:

World record3:13.20 Eugene, United States29 July 2016Championship record3:14.42 Nassau, Bahamas23 April 2017

Results KEY:QQualifiedqFastest non-qualifiersWLWorld leadingCRChampionship recordNRNational recordSBSeasonal bestWC2019 World Championships qualification

Heats Qualification: First 2 of each heat (Q) plus the 2 fastest times (q) advanced to the final.Heats ResultsHeats Summary Rank Heat Nation Athletes Time Notes 1 3 Kajetan Duszyński (M), Patrycja Wyciszkiewicz (W), Justyna Święty-Ersetic (W), Karol Zalewski (M) 3:15.46 Q, WL, AR, *WC 2 3 Brionna Thomas (W), My'Lik Kerley (M), Olivia Baker (W), Dontavius Wright (M) 3:16.01 Q, SB, *WC 3 3 Davide Re (M), Giancarla Trevisan (W), Andrew Howe (M), Raphaela Lukudo (W) 3:16.12 q, NR*,Italian Federation considers this time only as a Best performance and not a National record because the time is not quicker as 3:16. *WC 4 2 Austin Cole (M), Aiyanna Stiverne (W), Alicia Brown (W), Philip Osei (M) 3:16.78 Q, NR, *WC 5 2 Tobias Lange (M), Laura Müller (W), Nadine Gonska (W), Torben Junker (M) 3:16.85 Q, NR, *WC 6 2 Jared Nyambweke Momanyi (M), Maureen Nyatichi Thomas (W), Hellen Syombua (W), Aron Koech (M) 3:16.90 q, NR, *WC 7 1 Julien Watrin (M), Camille Laus (W), Liefde Schoemaker (W), Dylan Borlée (M) 3:18.03 Q, NR, *WC 8 1 Lucas Carvalho (M), Tiffani Marinho (W), Cristiane Silva (W), Alexander Russo (M) 3:18.26 Q, AR, *WC 9 1 Fitzroy Dunkley (M), Janieve Russell (W), Rhonda Whyte (W), Jamari Rose (M) 3:18.47 NR, *WC 10 3 Wilfried Happio (M), Kellya Pauline (W), Estelle Perrossier (W), Nicolas Courbiere (M) 3:18.93 NR, *WC 11 3 Rikuya Ito (M), Seika Aoyama (W), Mayu Inaoka (W), Naoki Kitadani (M) 3:19.71 NR, *WC 12 2 Alex Haydock-Wilson (M), Finette Agyapong (W), Anyika Onuora (W), Jamal Rhoden-Stevens (M) 3:20.49 NR, *WC 13 2 Lu Zhiquan (M), Wang Chunyu (W), Huang Guifen (W), Yu Yang (M) 3:21.66 14 1 Ian Halpin (M), Rebecca Bennett (W), Angeline Blackburn (W), Luke Stevens (M) 3:21.80 SB 15 1 Jithu Baby (M), Sonia Baishya (W), Prachi (W), Antony Alex (M) 3:23.59 16 2 Andrey Sokolov (M), Svetlana Golendova (W), Elina Mikhina (W), Mikhail Litvin (M) 3:24.54 3 Emmanuel Wanga (M), Leonie Beu (W), Shadrick Tansi (M), Isila Manukip Apkup (W) R170.19Starting outside the takeover zone 1

Final Final Results Rank Nation Athletes Time Notes Points My'Lik Kerley (M), Joanna Atkins (W), Jasmine Blocker (W), Dontavius Wright (M) 3:16.43 8 Austin Cole (M), Aiyanna Stiverne (W), Zoe Sherar (W), Philip Osei (M) 3:18.15 7 Jared Momanyi (M), Maureen Thomas (W), Hellen Syombua (W), Aron Koech (M) 3:19.43 6 4 Giuseppe Leonardi (M), Virginia Troiani (W), Chiara Bazzoni (W), Alessandro Sibilio (M) 3:20.28 5 5 Przemysław Waściński (M), Małgorzata Hołub-Kowalik (W), Justyna Saganiak (W), Patryk Dobek (M) 3:20.65 4 6 Lucas Carvalho (M), Tiffani Marinho (W), Cristiane Silva (W), Alexander Russo (M) 3:20.71 3 7 Marc Koch (M), Corinna Schwab (W), Svea Köhrbrück (W), Marvin Schlegel (M) 3:22.26 2 8 Julien Watrin (M), Lucie Ferauge (W), Hanne Claes (W), Jonathan Sacoor (M) 3:25.74 1

References