Treatment of choice for cervical dystonia is botulinum toxin (BTX) injection and surgical interventions can be tried in refractory cases. Success of BTX injection depends on precise muscle selection and adequate dosage of BTX. 18F- fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) can evaluate the metabolism of the superficial and deep cervical muscles with high resolution and may be useful for identifying dystonic muscles in CD. We report a satisfactory result of BTX injection using 18F-FDG PET/CT for identification of dystonic muscles in a patient with cervical dystonia who previously failed to respond to botulinum toxin injection and denervation operation. (J Korean Acad Rehab Med 2010; 34: 91-95)