Discoid medial meniscus is very rare and bilateral discoid medial meniscus is extremely rare. We report symptomatic bilateral discoid meniscus with abnormal attachment to anterior cruciate ligament (ACL) in three patients and we think that our report is a combination of very rare conditions. The patients had symptoms in both sides and we performed magnetic resonance imaging (MRI) and operated five knees. The operation methods were different by the condition of menisci.