Fighters
| first | last | nickname |
|---|---|---|
| Amir | Sadollah | |
| Alessio | Sakara | "Legionarius" |
| Ivan | Salaverry | |
| Diego | Sanchez | "Nightmare" |
| Eddie | Sanchez | "The Manic Hispanic" |
| Jorge | Santiago | |
| Ben | Saunders | "Killa B" |
| Eric | Schafer | "Ravishing Red" |
| Samy | Schiavo | |
| Pete | Sell | "Drago" |
| Matt | Serra | "The Terror " |
| Dan Severn | Severn | "The Beast" |
| Ken | Shamrock | "The World's Most Dangerous Man" |
| Sean | Sherk | "Muscle Shark" |
| Anderson | Silva | "The Spider" |
| Thiago | Silva | |
| Wanderlei | Silva | "The Axe Murderer" |
| Dennis | Siver | |
| Scott | Smith | "Hands Of Steel" |
| Rameau | Sokoudjou | "The African Assassin" |
| Chael | Sonnen | |
| George | Sotiropoulos | |
| Tommy | Speer | "The Farmboy" |
| George | St. Pierre | "Rush" |
| Kalib | Starnes | |
| Jeremy | Stephens | "Lil' Heathen" |
| Joe | Stevenson | "Daddy" |
| Sam | Stout | "Hands of Stone" |
| Mike | Swick | "Quick" |
| Tim | Sylvia | "The Maine-iac" |