The accuracy of joint line tenderness in the diagnosis of meniscal tears was assessed in 129 knees. Arthroscopy was performed in each case to establish the diagnosis. The diagnosis was correct in 100 knees (77.5%) and incorrect in 29 (22.5%). A preoperative diagnosis of a medial meniscal tear was made in 63 knees and confirmed in 46 (73%) at arthroscopy. There were 46 true-positive, 17 false-positive, four false-negative and 62 true-negative results for the medial side. A lateral meniscal tear was suspected in 45 knees and confirmed in 39 (86.7%). Thus, 39 true-positive, six false-positive, two false-negative, and 82 true-negative interpretations were found. In this study, joint line tenderness as a test for lateral meniscal tears was accurate (93%), sensitive (95%), and specific (93%), but for medial tears the rates were lower.