Joe “The Brown Bomber” Louis, 66-3 (52), from 1937-1949 and was 26-1, in title fights, and has been known to have 25 world title defenses in the heavyweight division.
Germany’s Regina Halmich, 54-1-1 (16), was 2x WIBF Fly champion, 2x WIBF Super Fly champion. In title fights she was 44-1-1. She fought from 1994 to 2007. Since she won titles in three divisions her total defenses would be 41. Only problem is she defended her titles against 10 opponents making their debut’s and 3 with losing records.
In April of 1995 in Las Vegas, NV, Halmich lost her only fight in her ninth fight she lost to Yvonne Trevino, 1-1, of Arizona, for the vacant IBF Fly title. Due to a cut on her left cheek the fight was stopped after the fourth round. Both fighters scored knockdowns in the first round. Trevino weighed 112 and Halmich 108. It was the only time Halmich fought in the US. Trevino defended the title and ended up 9-5-1.
Argentina’s Omar “El Hurracan” Navarez, 49-4-2 (25), was the WBO Flyweight and WBO Super Flyweight champion. He was 28-3-1 in world title fights. He had 16 flyweight defenses and 11 super flyweight defenses. Claiming 27 defenses.