Purpose: The purpose of this study was to examine the relationship among isokinetic knee extensor strength in 60(circle)/sec, hop and vertical jump strength tests, and to determine differences between the involved and uninvolved leg in soccer players after anterior crudate ligament (ACL) reconstruction. Materials and methods: Thirty-seven soccer players (mean age: 25.16 +/- 6.5 years) who had undergone arthroscopic ACL reconstruction using bone-pateflar tendon-bone at a 6 month follow-up participated into isokinetic measurement in 60(circle)/sec (CYBEX 6000), hop and vertical jump (VJ) strength tests including involved and uninvolved leg. Mean time for testing was 26 weeks following surgery. Results: Uninvolved leg test results were better then involved leg results (p<0.05). Correlation coefficients between 60(circle)/sec extensor peak torque (PT) and hop test results with involved and uninvolved legs were r=.38 (p<0.05), r=0.60 (p<0.01), respectively. Correlation coefficients between 60(circle)/sec extensor PT and VJ test results with involved and uninvolved legs were r-0.22 (p>0.05), r=0.15 (p>0.05), respectively. The mean quadriceps muscle strength of the injured side was 75 % of that of the uninjured side. Conclusion: The results of this study suggested that knee extensor strength and hop tests of both sides were effective in the functional performance of the lower limb following ACL reconstruction. Knee functions tests were suggested as a reference guide for the outcome of rehabilitation program.