To determine if attitudes associated with body checking, emotional empathy, and aggression differ between players in body checking and non-body checking hockey leagues and to determine the influence of these attitudes on injury rates. Prospective cohort. Participants were randomly recruited by team from the Calgary Minor Hockey Association at the beginning of the 2006-2007 season. There were 283 participants from Pee Wee (aged 11-12 years), Bantam (aged 13-14 years), and Midget (aged 15-16 years) teams. Of 13 teams from the body checking league, 138 players participated, and of 24 teams in the non-body checking league, 145 players participated. Participants completed 4 self-report questionnaires: (1) Medical Questionnaire, (2) Body Checking Questionnaire, (3) Empathy Index for Children and Adolescents, and (4) Buss-Perry Aggression Questionnaire. Participants were followed through the season for injury reports. The injury definition included any hockey injury resulting in medical attention, the inability to complete a hockey session, and/or missing a subsequent hockey session. Body checking players reported more positive attitudes toward body checking (35.59; 95% confidence interval [CI]: 34.52-36.65) than non-body checking players (22.43; 95% CI, 21.38-23.49; t = -17.34; P < 0.00005). There was no significant difference in the empathy scores between cohorts (t = 1.51, P = 0.13). The mean aggression score for the body checking players (76.22; 95% CI, 73.18-79.25) was significantly higher than the mean for the non-body checking players (70.57; 95% CI, 67.35-73.80; t = -2.52; P = 0.013). Body checking seems to influence attitudes toward body checking and aggression, but attitudes toward body checking, empathy, and aggression did not influence injury rates.