We present medium-term results in 30 prospectively followed patients aged over 50 years at the time of ACL reconstruction (31 procedures); mean follow-up time was 46 months (range 24-95). Mean Lysholm score improved significantly from 63 pre-operatively to 93 at final review Cincinnati score from 49 to 89. In IKDC score 25 knees (81%) were considered normal or nearly normal and 6 abnormal; there were no severely abnormal results. Mean Tegner activity scores improved from pre-operatively from 3.7 to 5.2 at review. Mean side-to-side difference measured by the KT-1000 at maximal manual pressure was 2.7 mm; two knees had. a measured difference greater than 5 mm. The mean torque ratio for isokinetic flexion strength was 102% and for extension strength 94%. Poor results as determined by the three scoring systems were associated mainly with advanced articular degenerative changes (Outerbridge grade 3 or 4) seen at the time of reconstruction. Despite this all patients reported improvement in stability and overall function of the knee. Degenerative change itself was associated with increased time to surgery from injury. This study demonstrates that the ACL can be reliably reconstructed in patients over the age of 50 years with good symptomatic relief, restoration of function and return to sporting activity.