UFC Fight Night 136: Hunt vs. Oleinik was a mixed martial arts event produced by the Ultimate Fighting Championship held on September 15, 2018 at Olimpiyskiy Stadium in Moscow, Russia. The event marked the promotion's first visit to Russia. The UFC arranged to use half of the venue and used a modified seating configuration for the arena.  While not officially announced, the promotion was initially targeting a heavyweight bout between former UFC Heavyweight Champion Fabrício Werdum and Aleksei Oleinik to serve as the main event. However, on May 22, Werdum was flagged for a potential USADA doping violation and his status moving forward became unknown. On July 19, the promotion announced that a bout between the 2001 K-1 World Grand Prix winner and former interim title challenger Mark Hunt and Oleinik would serve as the event headliner.