A 17-year old boy presented with a 10-year history of progressive head tilt to the right. Bilateral posterolateral cervical pain was mild and he was fully functional. The right sternocleidomastoid (SCM) muscle was prominent without ratation of the head to the left. The SCM had a cord-like consistency on palpation. Magnetic resonance (MR) and computed tomography (CT) scan imaging of the neck musculature suggested fibrous tissue within the substance of the muscle. This was histopathologically confirmed when the right SCM was surgically explored and resected. Congenital muscular torticollis is usually seen in newborns, infants, and children but may also present in adolescence and young adulthood. It should be included in the differential diagnosis of cervical dystonia as one of the nondystonic causes of abnormal head posture. Combined use of MR and CT scan of neck muscles may be of help in the diagnosis.