The fastest marathon run by parent and child (mixed) is 5 hr 41 min 12 sec by Masako Kataoka and her son Tetsuro Kataoka (both Japan) at the 63rd Beppu Oita Mainichi Marathon in Beppu, Oita, Japan, on 2 February 2014.

The Beppu Oita Mainichi Marathon is sanctioned by the Japan Association of Athletics Federations (JAAF). Tetsuro Kataoka completed the marathon in 2 hr 31 min 20 sec and Masako Kataoka completed it in 3 hr 9 min 52 sec.