A common peroneal nerve palsy caused by a ganglion has been rarely reported. A Ganglion may arise from joint, tendon sheath or sheath of peripheral nerve. They may also be intraosseous and intraneural but relatively rare entities. Although intraneural ganglion is a well recognized entity, few reports in the literature describe motor weakness and sensory change as a primary clinical manifestation. The pathogenesis of intraneural ganglion cyst remains controversial. We describe the case of 42-year-old male manual worker with a 2 month history of weakness of the right ankle and foot drop and paresthesia of the anterolateral aspect of the lower leg, as a result of compression of the common peroneal nerve by a ganglion, in both intraneural and intramuscular forms.