Cysts of the meniscus are rare lesion of the knee. They may present as a local tumor or mimic signs of an internal derangement of the knee. So it is difficult to diagnose and apt to overlook in physical examination. Also they almost always have combined pathology of the involved meniscus, such as, meniscal tear or discoid meniscus. The pathologic basis of the meniscal cyst is controversial, but rece 2. Most of the patients had tear of the involved meniscus, but the patients with discoid meniscus did not have gross tears or previous trauma history. nt works suggest the etiology is infiltration of joint fluid through micro and macro tears in the meniscus. In the past, complete excision of the meniscus as well as cyst was thought to be the treatment of choice to prevent recurrences. But nowadays, the trend is changed as preserving the involved meniscus, when no tear of the meniscus is found to prevent enevitable degenerative changes after total meniscectomy. We experienced 6 cases of meniscal cyst during recent 2 years and obtained following results. 1. Precise joint line evaluation is much more important in the diagnosis of the meniscal cyst before making special study. 2. Most of the patients had tears of the involved meniscus, but the patients with discoid meniscus did not have gross tears or previous trauma history. 3. When the cyst is located anteriorly in the joint line, it is prominent in flexed position of the knee; and when located posteriorly, prominent in extended position of the knee. 4. Excision of the cyst and reattachment of the meniscus were thought to be good method when the cyst was located in the parameinscal area without gross tear of the involved meniscus.