There are seven on field officials in an American football game: referee, umpire, head linesman, line judge, side judge, field judge, back judge.
Click on the 'NFL Officials' link on this page to read about the duties that each official has during a game.
There is one referee and six other officials on the field during an NFL game. Click on the 'NFL Officials' link on this page to see the duties of each official on the field and what equipment they use during the game.
College basketball games generally have three officials. They is officially one referee and two umpires and the lead referee is referred to as the crew chief.
There are four referees in a baseball game.
3 referees are in soccer and football