We sought to compare the ability of the prehospital Canadian C-Spine Rule to selectively recommend immobilization in sport-related versus non-sport-related injuries and describe sport-related mechanisms of injury. We reviewed data from the prospective paramedic Canadian C-Spine Rule validation and implementation studies in 7 Canadian cities. A trained reviewer further categorized sport-related mechanisms of injury collaboratively with a sport medicine physician using a pilot-tested standardized form. We compared the Canadian C-Spine Rule's recommendation to immobilize sport-related versus non-sport-related patients using Chi-square and relative risk statistics with 95% confidence intervals. There were 201 sport-related patients among the 5,978 included. Sport-related injured patients were younger (mean age 36.2 vs. 42.4) and more predominantly male (60.5% vs. 46.8%) than non-sport-related patients. Paramedics did not miss any C-Spine injury when using the Canadian C-Spine Rule. C-Spine injury rates were similar between sport (2/201; 1.0%) and non-sport-injured patients (47/5,777; 0.8%). The Canadian C-Spine Rule recommended immobilization equally between groups (46.4% vs. 42.5%; RR 1.09 95%CI 0.93-1.28), most commonly resulting from a dangerous mechanism among sport-injured (68.7% vs. 54.5%; RR 1.26 95%CI 1.08-1.47). The most common dangerous mechanism responsible for immobilization in sport was axial load. Although equal proportions of sport and non-sport-related injuries were immobilized, a dangerous mechanism was most often responsible for immobilization in sport-related cases. These findings do not address the potential impact of using the Canadian C-Spine Rule to evaluate collegiate or pro athletes assessed by sport medicine physicians. It does support using the Canadian C-Spine Rule as a tool in sport-injured patients assessed by paramedics.