Masakatsu Ueda is a professional Japanese mixed martial artist who currently competes in the bantamweight division, known as featherweight in Shooto, where he was the former Shooto Featherweight Champion. Ueda won the vacant title after defeating Koetsu Okazai on March 28, 2008 by unanimous decision at Shooto's Back To Our Roots 8 show. Ueda was also a college level wrestler in Japan where he held a win over fellow mixed martial artist and Japanese superstar Norifumi Yamamoto. Ueda has also won many national titles in combat wrestling. He also won the All Japan Shooto Grappling Championship, and both A and B class Shooto Rookie Tournaments.

Ueda first defended his Shooto title against Marcos Galvao at Shooto - Tradition 3 where they fought to a draw. His next defense came against So Tazawa at Shooto - Tradition 6 where he defeated Tazawa via unanimous decision. Ueda then defeated Eduardo Dantas at Shooto - Revolutionary Exchanges 1: Undefeated via unanimous decision in his third defense. In his fourth title defense he lost to Shuichiro Katsumura via submission in the second round, losing the title in the process.

After winning 5 fights in a row, Ueda entered the Bellator Season 6 Bantamweight Tournament where he faced Travis Marx. Ueda would lose to Marx via unanimous decision and was eliminated from the tournament.

After his tournament loss Ueda fought for ONE FC where he went 3-0 competing in their bantamweight tournament. Ueda defeated Min Jung Song (ONE FC 6), Jens Pulver (ONE FC 8) and Kevin Belingon (ONE FC 9) on his way to win the tournament.