400m Hurdles is a 400-meter race with ten hurdles, and is an Athletics (Track) event in Mario & Sonic at the Olympic Games. The goal of the event is to cross the finish line first while jumping over hurdles. The event shares many properties with the 400m race and 110m Hurdles.
Racers will begin the race at their starting line. When the announcer announces On Your Marks and Get Set pressing on the will cause the character to ready themself and build up potential energy. Once the gunshot is heard releasing and swinging down the wii remote will give the player a boost. Running is controlled by alternating the movement of the wii-mote and Nunchuk. The player must press the button for the participant to jump over the hurdle.
Like the 400m, the characters have stamina that will run out if they run too fast. If it depletes, the player will stop running for a short time as the meter refills. If it runs out when a racer is about jump over a hurdle, the timing of the jump must be precise or else the obstacle will not be cleared. The sprint at the last hundred meters is also present. Like the 110m, if a hurdle is completed with perfect timing, a speed boost will be received. If the player hits a hurdle, their current speed will disappear and they will be stumbled.
 Wii Version
Bowser's third mission in the Wii version of Mario & Sonic at the Olympic Games is 400m hurdles. To win it Bowser must finish the race but the necessary requirements for placement are not that he place in first but that he place between forty-five and fifty-three seconds time once the race is done. Another slight problem for the race is that Bowser must complete the race without knocking down a single hurdle. Bowser must have great timing to miss all the hurdles and still arrive in the correct amount of time.
Princess Daisy's third mission in the Wii version is both 400m hurdles and the same thing as Bowser's third mission in the Wii version. To win, she must also place not in a numbered place but in a timed place (also between forty-five and fifty-three seconds) and she must still not knock down any of the many hurdles strewn across her path. If she hits a single hurdle, she loses the mission and maybe the race as well.
Wario's sixth, final and hardest mission in the Wii version is 400m hurdles. To win the mission, Wario must travel along the race track and pass his rival, Luigi, before the end of the race. Luigi starts ahead of Wario, but Wario has the inside track therefore giving him the advantage in the race.
Sonic's fifth mission in the Wii version is 400m hurdles. To win, the speedy hedgehog must cross the finish line first. At the end of the race, Sonic must use up all of his energy sprinting so that he is so tired that he staggers across the finish line.
 DS Version
Daisy's first mission in the DS version of Mario & Sonic at the Olympic Games is 400m hurdles. To win this mission, Daisy must do what was done two times in the Wii version, once by Daisy herself, as a mission in the DS version, the only difference being that in the DS version there was a time limit. This thing that Daisy must do is, once again, win the race without knocking down a single hurdle though this time she can score with any time (as long as she comes in first) and not just between to preset times.
Yoshi's sixth, final and hardest mission in the DS version is his boss battle against his sonic series counterpart in top condition. Yoshi's enemy in this race of races is the flying fox of the Sonic series, Tails.
Waluigi's first mission in the DS version is 400m hurdles. To win it Waluigi must simply cross the finish line at the end of the race before all of the other competitors in the race, the racers, cross the finish line. There is a problem with Waluigi's start at the beginning of the race in that he will have to wait three seconds after everybody else starts to start thus giving him a three second handicap in the race which he will have to come in first with.
Sonic's third mission in the DS version is 400m hurdles. To win this mission Sonic must run the race and win it but he must perform a maneuver a total of seven whole times during the course of the race. The maneuver that Sonic must perform seven times in the race is called a sprint jump; it is done by tapping the bottom screen with the stylus to make Sonic jump and, because of the jump, speed up. If Sonic sprint jumps six times or less, he loses the mission though that does not necessarily mean he loses the race.