General aim of this study is to compare the effects of isokinetic and isotonic exercise on therehabilitation results in patients three months after surgical reconstruction of the anterior cruciateligament. A sample of 180 subjects was analyzed, divided into two subsamples in relation to thetype of rehabilitation treatment that was performed. The examined group A-isokinetic, consistedof 90 male subjects, at the average age of 28.54±4.44. Their rehabilitation protocol was based onisokinetic exercise of the upper leg muscles. The examined group B-isotonic (classical),consisted of 90 male subjects, at average age of 27.93±4.27. In the case of these subjects, anexercise program with additional resistance was applied in the rehabilitation protocol forstrengthening the lower leg muscles, i.e. isotonic exercise in the gym.Before the start of the rehabilitation treatment, an initial isokinetic test was performed at anangular velocity of 60°/s in all subjects. After three and six weeks of rehabilitation treatment,control tests were performed in the same way and the same parameters were followed as in theinitial test. Based on the values of MANOVA analysis and DISCRIMINATIVE analysis,significantly better results of isokinetic tests were found in the examined group A – isokinetic,compared to the examined group B –isotonic. The difference between the examined groups wasmore significant at the final measurement after six weeks of rehabilitation treatment compared tothe control measurement after three weeks of testing.Based on the results of the research, we conclude that isokinetic exercise is more effective interms of rehabilitation of the lower leg muscles after the reconstruction of the anterior cruciateligament.