Aim. Assess the results of the reconstruction of the anterior cruciate ligament (ACL) in patients over 40 years after a minimum follow-up of 24 months. Material and Methods. Retrospective review of 37 patients undergoing surgery for ACL reconstruction between 2002-2013, over 40 years with a minimum follow-up of 24 months. 25 patients were available for clinical review, which consisted of physical examination, radiographic and arthrometric KT-1000 studies, functional tests and subjective assessment of the knee through surveys (International Knee Documentation Committee (IKDC), Tegner and Lysholm-Tegner). Results. At follow-up, at least 2 of the 3 knee instability maneuvers (Pivot-shift, Lachman, Anterior drawer test) were positive in 6 of 25 patients (24%). The difference of antero-posterior laxity compared with the healthy knee using KT-1000 arthrometer to 89N was greater than 3mm in 5 patients (20%). None had a greater difference of 5mm. Only 6 patients recovered their previous level of activity, according to the Tegner test. However, the average score on the Lysholm test was 81,40 ± 19,56 points, with good or excellent results in 15 patients (60%). IKDC test results were less conspicuous, with good or excellent results in 7 patients (28%). Conclusions. The results after ACL reconstruction in patients older than 40 years old are good, with a high degree of satisfaction and are comparable to those in younger patients. Although return to previous activity level is less than in younger groups, age should not be a limiting to indicate an ACL reconstruction factor in an unstable knee.