Bat-Ochiryn "Ziggy" Ser-Od is a Mongolian long-distance runner, particularly the marathon. He represented his country in the marathon at five Summer Olympics, in 2004, 2008, 2012, 2016 and 2021. A member of the Morpeth Harriers running club, he divides his time between his native country and Gateshead in England.

The men's marathon at the 2008 Summer Olympics took place on 24 August at 7:30am in Beijing, ending in the Beijing National Stadium. It was the last time in Summer Olympics history that the start and/or finish of the men's marathon route was located inside the Olympic Stadium. Ninety-five athletes from 56 nations competed. The winner of the event was Samuel Wanjiru of Kenya, who set an Olympic record in the time of two hours, six minutes, and 32 seconds. It was Kenya's first victory in the men's marathon. Morocco won its first medal in the event since 1960, with Jaouad Gharib's silver. Tsegay Kebede of Ethiopia took bronze.