While several studies have documented the incidence of injury in senior rugby league players, information on the injury rates of junior rugby league players is limited. In addition, all of the injury surveillance studies performed on junior rugby league players have been performed over a limited time frame (typically one season). The purpose of this study was to document the incidence of injury in junior rugby league players over four competitive seasons. Injury data were collected from 84 matches. An injury was defined as one that occurred in a match and resulted in the player missing a subsequent match. The overall incidence of injury was 56.8 (95% CI, 42.6-70.9) per 1000 playing hours. The majority of injuries were sustained to the shoulder (15.6 [95% CI, 8.2-23.0] per 1000 playing hours). Sprains were the most common type of injury (24.7 [95% CI, 15.4-34.1] per 1000 playing hours). Injuries were most commonly sustained while being tackled (19.2 [95% CI, 11.0-27.5] per 1000 playing hours) and while tackling (10.1 [95% CI, 4.1-16.0] per 1000 playing hours). While there was a tendency towards differing injury rates over the four competitive seasons (chi(2)=6.3, d.f.=3), the differences were not statistically significant (p=0.10). These findings demonstrate that the incidence of junior rugby league injuries is similar to previously reported for senior competitors. A long-term collaborative effort to reduce the incidence of injury in junior rugby league players is warranted.