UFC 37: High Impact (5/10/02) Kosaka lost to Ricco Rdriguez by TKO (Strikes) at 3:25 min of the second round.
UFC 23: Ultimate Japan 2 (11/19/99) Kosaka lost to Pedro Rizzo by TKO (Strikes) at 1:12 min of the third round.
UFC 21: Return of the Champions (7/16/99) Kosaka defeated Tim Lajcik by TKO (Corner Stoppage) at 5:00 min of the second round.
UFC 18: Road to the Heavyweight Title (1/8/99) Kosaka lost to Bas Rutten by KO at 14:15min.
UFC Brazil: Ultimate Brazil (10/16/98) Kosaka defeated Pete Willias by decision.
UFC 16: Battle in the Bayou (3/13/98) Kosaka defeated Kimo Leopoldo by decision.