The pyriformis syndrome is a rare entrapment neuropathy in which the sciatic nerve is compromised by the pyriformis muscle or other local structures. It is an important cause of buttock pain that may often be accompanied by sciatica. The pain is usually increased by muscular contraction, palpation or prolonged sitting. The diagnosis relies on the clinical presentation and the electromyelography (EMG) findings. Other causes of symptoms should be excluded by careful examination and detailed neuroradiological studies of the lumbosacral spine, sacro-iliac and hip joints. A case of this syndrome seen in a 36-year-old man who recovered by CT-guided corticosteroid injection is reported.