This is the progression of world record improvements of the 400 metres hurdles M45 division of Masters athletics.
- Key
Incomplete information Pending
| Hand | Auto | Athlete | Nationality | Birthdate | Age | Location | Date | Ref |
|---|---|---|---|---|---|---|---|---|
| 53.57 | Aramis Diaz |  Italy | 22 November 1974 | 45 years, 288 days | Rome | 5 September 2020 | ||
| 53.90 | Aramis Diaz | Italy | 22 November 1974 | 45 years, 281 days | Padua | 29 August 2020 | ||
| 54.92 | Edward Betts |  United Kingdom | 18 February 1971 | Palencia | 9 July 2016 | |||
| 55.18 | Guido Müller |  Germany | 22 December 1938 | Malmö | 1 August 1986 | |||
| 55.7 | Jack Greenwood |  United States | 5 February 1926 | San Diego | 24 August 1972 |