We assessed the accuracy of clinical evaluation, arthrography and arthroscopy in the diagnosis of meniscal lesions in ninty knees in which arthrotomy was performed for disabling symptoms after evaluation by these three methods. At surgery, ninty-two menisci were removed, of which seventy-two were abnormal and twenty were normal. In these ninty-two menisci, correct diagnostic rate was made clinically 78%, arthrographically 70% and arthroscopically 86%. Arthrographic diagnosis was least accurate for lesions of the lateral meniscus and arthroscopic diagnosis was least accurate for lesions of the posterior horn of the medial meniscus and peripheral lesions. Based on this study, it was concluded that both the arthrography and arthroscopy are valuable technique for diagnosis of meniscal lesions.