Ganglion cysts are benign cystic lesion arising from the tendon sheath and joint capsule. Intraarticular ganglia of the knee are rare and cysts originating from the posterior cruciate ligament are uncommon compared to those growing out of the anterior cruciate ligament. Mostly, they are accidentally found during magnetic resonance imaging (MRI) or arthroscopy. MRI is recognized as the gold standard in characterizing cystic lesions around the knee. Treatment modalities including arthroscopic resection, ultrasound- and computed tomography-guided aspiration have been described. We aimed to present a case of ganglion cyst associated with the posterior cruciate ligament, treated by aspiration under ultrasound guidance. Turk J Phys Med Rehab 2010;56:207-9.