Background Discoid lateral meniscus of the knee is common in Chinese population. There has been considerable debate about the best treatment for discoid lateral meniscus tears. The purpose of this study was to observe the effect of arthroscopic meniscectomy for the treatment of discoid lateral meniscus tears. Methods Between July 1999 and December 2004, arthroscopic meniscectomy was performed on 62 menisci of 57 patients with discoid lateral meniscus tears (52 unilateral, 5 bilateral). 41 menisci were "complete discoid meniscus", 21 "incomplete". According to the extent of the meniscus tears, partial meniscectomy was performed on 52 knees, total meniscectomy on 7 knees, and partial meniscectomy combined with meniscus suture on 3 knees through an arthroscope. After the operations, early rehabilitation training programs, including straight-leg-raising and range-of-motion exercises, were carried out. 51 patients were followed up for 1 year 2 months to 6 years 5 months (mean, 3 years 3 months), 6 patients were lost. Lysholm-II scoring system was used to assess the function of the knee joints before the operation and during the follow-up. Results The operations on all the 62 knees were successful without complications. The patients could walk normally after completing the 2-week postoperation rehabilitation program. After 3-4 weeks they could lead a normal life and participate in a moderate amount of sports or other physical activities. The mean Lysholm-II score was 89 (60-100) during the follow-up, which was significantly higher than that before the operation (50, range 34-74; P < 0.01). 88% of the patients achieved excellent or good clinical results. Conclusions Arthroscopic meniscectomy is an alternative for treatment of discoid lateral meniscus tears with minimal traumatic effects. It can achieve early mobilization and a low complication rate, as well as the preservation of the meniscus structure and functions to the largest extent. In combination with proper rehabilitation training, the operation can lead to good or excellent results.