PURPOSE: To validate the functional performance tests (FPTs) after anterior cruciate ligament (ACL) reconstruction. MATERIALS AND METHODS: Thirty men in their third decade after ACL reconstruction at 6 month follow-up and thirty healthy subjects were selected. Lysholm knee score, International Knee Documentation Committee (IKDC) subjective score, Tegner activity score, KT-2000 arthrometer test, isokinetic strength test, functional performance tests (one leg hop test, co-contraction test, shuttle run test, carioca test) were performed in two groups. We evaluated the test-retest reliability of FPTs in healthy group and the between FPTs and other parameters in ACL reconstruction group. RESULTS: The test-retest result showed high correlation in co-contraction test (r=0.511), shuttle run test (r=0.746), carioca test (r=0.742). In the ACL reconstruction group, the IKDC score, Tegner activity score, extensor power at 60degrees/s, and one leg hop test also showed high correlation between each test. CONCLUSIONS: The three FPTs showed correlations with the established methods for determining return to sports activities after ACL reconstruction and had high test-retest reliability. Therefore we believe the three FPTs can be useful methods to assess knee function in athletes after ACL reconstruction.