This study investigated the relationship between exposure time and injury in football and the trends associated with these relationships. Data were collected at all practice sessions and games participated in by the University of Illinois varsity football team during the 1976 and 1977 seasons. Subjects consisted of the varsity football team at the University of Illinois. The 54 members of the traveling squad were the subjects used in the collection of game and injury data. Games were divided into three intervals and practice into five 25-min intervals in order to analyze the data. A likelihood ratio tests was used to test the data for statistical significance. An inverse relationship was found between exposure time and injuries for game data for both years. A curvilinear relationship, slightly skewed to the right, was found between exposure time and injuries for game data for both years. A curvilinear relationship, slightly skewed to the right, was found between exposure time and injury for the practice data for both seasons.