Purpose: To assess the histological findings of anterior cruciate ligament (ACL)degeneration inanarthritic knee and its correlation with the gross appearance of the ACL, the patient s age and the functional status of the knee. Materials and Methods: Histological evaluations of the ACL were carried outon 80 patients who had total knee arthroplasty. Five types of ACL degeneration were noted; 1) mucoid degeneration, 2) liquefaction, 3) hyaline degeneration, 4) calcification, and 5)fissuring. A scoring system for the level of ACL degeneration was made. Each type of degeneration was scored and the degree of ACL degeneration was graded by summing each score. The correlation between ACL degeneration and patient's age, gross appearance, and functional evaluation of knee by Knee Society Score (KSS) was analyzed. The gross appearance of the ACL was classified as normal, (thinned or hypertrophied), and tear. Results: The scores for the histological degeneration of theACL ranged from 2 to 10,andthere was no correlation between the patient's ageand the scores (p>0.05). Thegross appearance of the ACL was normal in 19 cases, abnormal in 57, and tear in 4 with an average score of histological degeneration in 3.47 (2-6), 5.95 (3-10), and 9.0 (8-10) respectively. The score for the histological degeneration of the ACL was correlated with the gross appearance of the ACL and a functional evaluation by the K55 (p