Only a few cases of cyst related to cruciate ligament were reported in the literatrure. It is not only because of rarity but also difficulty of diagnosis by conventional method. Recentely, the precise intraarticular structure of the knee joint became to be seen by introduction of MRI and arthroscope and cycts would bave been found incidentally during the workup of the internal derangement of knee. We have experienced three cases of ganglion around the cruciate ligament in the patients whose symptom was mimic of intemal derangement of knee. We excised the ganglion with good clinical results.