With increased use of magnetic resonance imaging (MRI) and arthroscopy, intra-articular ganglion cysts of the posterior cruciate ligament (PCL) have received more recognition as a possible cause of knee discomfort. Reported treatment options have ranged from ultrasound-guided cyst aspiration to arthroscopic cyst resection. In this report, we present the case of a patient who, on MRI, was diagnosed with a symptomatic intrasubstance PCL ganglion that later, during surgery, demonstrated mucinous degeneration of the entire ligament. Treatment was complete resection of the PCL. Five years after surgery, the patient demonstrated excellent, asymptomatic knee function. Although the best treatment for an intrasubstance PCL ganglion cyst that has caused degeneration of the entire ligament is unknown, PCL resection without reconstruction should be considered a viable option. It can result in a large increase in range of motion and function.