Here is a list of Castillo's best fights. For a list of Castillo's losses, refer to "Gil Castillo Losses".
On January 11, 2002 Gil Castillo faced off against Chris Brennan in a welterweight bout at age 36. He was coming in with a record of 9-1 (5), and Brennan was 30 years old and with a record of 11-4-1 (10). Castillo won the fight via 3-round unanimous decision.
On October 14, 2005 Gil Castillo faced off against Steve Ramerez in a welterweight bout at age 39. He was coming in with a record of 11-4 (7). Castillo stopped Steve Ramerez via TKO.
On March 27, 2003 Gil Castillo faced off against Chris Williams in a welterweight bout at age 37. He was coming in with a record of 10-2 (6). Castillo stopped Chris Williams via TKO.
On July 18, 2001 Gil Castillo faced off against Nate Marquardt in a welterweight bout at age 35. He was coming in with a record of 8-0 (5), and Marquardt was 22 years old and with a record of 12-1-1 (10). Castillo won the fight via 5-round unanimous decision.
On April 29, 2001 Gil Castillo faced off against Joe Hurley in a middleweight bout at age 35. He was coming in with a record of 7-0 (5). Castillo won the fight via 3-round unanimous decision.