This retrospective study compared the results after anterior cruciate ligament (ACL) reconstruction using a four-strand hamstring tendon graft (4SHG) versus Ligament Advanced Reinforcement System (LARS) artificial ligament in 60 patients between January 2003 and July 2004 with a minimum four-year follow-up. The KT-1000 examination, the International Knee Documentation Committee (IKDC) scoring systems and Lysholm knee scoring scale were used to evaluate the clinical results. The mean side-to-side difference was 2.4 +/- 0.5 mm and 1.2 +/- 0.3 mm in the 4SHG group and LARS group, respectively (P = 0.013). Although other results of ACL reconstruction, measured by IKDC evaluation, Lysholm scores and Tegner scores, showed using a LARS graft clinically tended to be superior to using a 4SHG, there were no significant differences calculated. Our results suggest that four years after ACL reconstruction using a LARS ligament or 4SHG dramatically improves the function outcome, while the patients in the LARS group displayed a higher knee stability than those in the 4SHG group.