Naiel Santiago D'Almeida was 21 years old at the time of the 2008 Olympics, and competing in his first Olympics. On 18 August 2008, he took part in the heats of the Men's 400 meters race. He was drawn into the 7th and final heat of the race, a race he finished in 49.08 seconds. This was last in his heat, and the second slowest time of all the competitors. As such, he failed to advance to the semi-finals.