The incidence of aggression in ice hockey and the consequences of violent on-ice behavior is of major concern to those interested in the safety of the sport. The purpose of this paper is to examine the history of aggression in hockey, how it is measured and why it happens. A hypothetical integrated model of antecedents of aggression in hockey is presented which may guide future research investigations. Officiating in ice hockey, penalty statistics at specific levels of participation, and the categorization of penalties are discussed. An assessment was done to determine whether there has been a change in player's perceptions of the attitudes of significant others toward aggression. The results were compared to previous research [1], which examined reinforcers of aggressive behavior in hockey players. A case study of an injured hockey player is presented which depicts the physical and psychosocial consequences of a penalized aggressive on-ice incident. Steps that can be taken to reduce aggression and identify barriers that are likely to impede attempts to reduce aggression in the game will be discussed. Suggestions for future research are presented.