From September 1983 to June 1988, the authors could experience 104 cases of meniscal injury from 99 patients by arthroscopic examination. The results of this study may be summarized as follows : 1. There were noticed 35 cases of medial meniscus tear, 35 cases of lateral discoid meniscus tear, 12 cases of intact lat discoid meniscus, 1 case of medial discoid meniscus and 3 cases of lateral meniscal cyst. 2. Most common type of meniscal tear was bucket handle type (35 cases, 34.6%). 3. Most common site of rupture was posterior horn of medial meniscus. 4. Post operative results appeared related with the type of meniscus rupture and combined pathology of knee jont. Bucket handle type rupture was of good prognosis and meniscus lesions with chondromalacia was of poor prognosis.