In the 1900 Olympics, the distance was modified to 400 metres with ten hurdles of 91.44cm (3ft) in height, separated by 35 metres. The first hurdle was placed 45 metres from the start, the tenth 40 metres from the finish. These metric distances have remained unchanged ever since.

The technical development of this event has mirrored that of the 110m hurdles, with the adoption of mobile hurdles and, later, synthetic tracks.Performance evolution has come as specialists have become faster and stronger, so needing fewer strides between hurdles.

The current world record of 46.78 was set by Kevin Young (USA) - also known as "Spiderman"- who successfully switched from 12 to 13 strides between barriers when most of his rivals were running 13 to 14 strides.

The first women's race at this distance, with 10 flights of 76cm (2ft 6in) high hurdles, took place in 1971. The IAAF officially sanctioned the event in 1974 and it was part of the 1983 IAAF World Championships. The first Olympic gold was won the following year by Nawal El Moutawakel (Morocco), who became the first woman to be elected to the IAAF Council in 1995.