Spontaneous retropharyngeal hematoma is rare and difficult to diagnosis early. A 23-year-old male spontaneously developed acute onset of neck pain, limitation of neck motion, and mild dysphagia. Magnetic resonance imaging demonstrated blood products in prevertebral space from C2 to C4, suggesting a diagnosis of retropharyngeal hematoma. We report a rare case of spontaneous retropharyngeal hematoma causing neck pain.