Horizontal tear of the meniscus occurs most commonly in older patients. The tear begins initially with a simple horizontal cleavage which divides the meniscus into superior and inferior leaves resembling a fish mouth and which may become a flap or more complex tear with time if subjected to repeated injury. Thirty-four patients(36knees/40menisci) with horizontal tear of the meniscus, treated with arthroscopic partial meniscectomy except in 3 extensive tears at Ulsan University Hospital from Jan. 1993 to Jun. 1996, were analyzed to investigate the factors that may be associated with this type of meniscal tear, and the results were as follows;