The purpose of this study was to identify effects of an aquatic therapy program on patients with anterior cruciate ligament injuries. All of the patients responded to notices containing a description of the study that were posted in the rehabilitation center where the study were conducted. Participants registered for the program in the rehabilitation center, obtained physician`s permission to participated, and completed required registration forms. 16 participants were randomly assigned into two groups: an aquatic therapy program group(N 8), a physical therapy group(N 8). All of the participants completed the exercise during one hour a day, three days a week for 12 weeks. The following results were found in the study: 1. Changes of extensor and flexor at 60°/sec Although no significant difference was found between two groups, an aquatic therapy group and a physical therapy group with respect to the measures of peak torque, there were significant increases between two groups over training time. While there progressively increases between two groups with respect to the measures of peak torque on the uninvolved side at 60°/sec, there was not found significant difference between two groups over training time. No significants difference was found in both involved side and uninvolved side by the training period. The training group showed a quick recovery fro m the muscle functions, followed by a aquatic therapy group. This study also revealed significant differences training period X both involved and uninvolved side X group interaction. 2. Changes of extensor and flexor at 180°/sec in % body weight in the peak torque % body weight of extensor and flexor at 180° /sec, no significant difference was found between two groups. No significants difference was found in both involved side and uninvolved side by the training period. The training group showed a quick recovery from the muscle functions, followed by a aquatic therapy group. This study also revealed significant differences training period X both involved and uninvolved side X group interaction. in summary, as a result of 12weeks of rehabilitation program, there were differences between two muscular functions, while not significantly different from each other. This was showed differences in the muscular functions of both involved and uninvolved side between two groups by the treatment period. Although aquatic therapy group showed a quick recovery from the muscular functions, followed by physical therapy group, there was no significant difference. These findings suggest that aquatic therapy program is more effective interventions to the patients with ACL injuries than physical therapy.