Synovial chondromatosis is a rare condition characterized by benign chondrogenic meta- plasia of extra-articular synovial tissue. It usually affects a single tendon sheath of the hand or foot. This report describes a rare case with extensive synovial chondromatosis affecting all flexor tendons in the tarsal tunnel, its radiological features, surgical treatment, and clinical outcome. The authors present a unique case of extensive synovial chondromatosis in a 48-year-old male involving the tendon sheaths of the flexor hallucis longus, flexor digitorum longus, and posterior tibialis tendons, at the level of the tarsal tunnel, with extension into the plantar aspect of the foot. The patient initially presented with symptoms of tarsal tunnel compression and was found to have a 4-cm mass in the posteromedial aspect of the ankle. The presumptive diagnosis of synovial chondromatosis was made based on radiographic and magnetic resonance imaging evidence. The patient underwent surgical resection of the tumor, as well as tarsal tunnel release and gastrocnemius recession. The diagnosis was confirmed postoperatively by surgical histopathology. The postoperative course of the patient was uncomplicated and his tarsal tunnel symptoms resolved. This represents a case of extensive synovial chondromatosis involving all flexor tendons in the tarsal tunnel that was correctly diagnosed by clinical and imaging findings, which required early surgical resection to avoid long-term neurovascular complications.