Prior to Official Recognition
| Time | Team | Country | Venue | Date | Ref |
|---|---|---|---|---|---|
| 3:13.20 | Kyle Clemons Claudia Francis James Harris Phyllis Francis |  United States | Eugene | 29 July 2016 | [1] |
The following table shows the world record progression in the mixed 4 x 400 metres relay. The first world record in the event was recognised by the International Association of Athletics Federations in 2019.
| Time | Team | Country | Venue | Date | Ref |
|---|---|---|---|---|---|
| 3:13.20 | Kyle Clemons Claudia Francis James Harris Phyllis Francis | United States | Eugene | 29 July 2016 | [1] |
Awaiting ratification
| Time | Team | Country | Venue | Date | Ref |
|---|---|---|---|---|---|
| 3:12.42 | Tyrell Richard Jessica Beard Jasmine Blocker Obi Igbokwe | United States | Doha | 28 September 2019 | [2] |
| 3:09.34 | Wilbert London Allyson Felix Courtney Okolo Michael Cherry | United States | Doha | 29 September 2019 | [3] |
| 3:08.80 | Justin Robinson Rosey Effiong Matthew Boling Alexis Holmes | United States | Budapest | 19 August 2023 | [4] |
The 400 metres, or 400-meter dash, is a sprint event in track and field competitions. It has been featured in the athletics programme at the Summer Olympics since 1896 for men and since 1964 for women. On a standard outdoor running track, it is one lap around the track. Runners start in staggered positions and race in separate lanes for the entire course. In many countries, athletes previously competed in the 440-yard dash (402.336 m)—which is a quarter of a mile and was referred to as the "quarter-mile"—instead of the 400 m (437.445 yards), though this distance is now obsolete.
The 4 × 400 metres relay or long relay is an athletics track event in which teams consist of four runners who each complete 400 metres or one lap. It is traditionally the final event of a track meet. At top class events, the first leg and the first bend of the second leg are run in lanes. Start lines are thus staggered over a greater distance than in an individual 400 metres race; the runners then typically move to the inside of the track. The slightly longer 4 × 440 yards relay, on an Imperial distance, was a formerly run British Commonwealth and American event, until metrication was completed in the 1970s.