Pyomyositis in the neck has rarely been described. We present the sonographic findings in a case of pyomyositis of the sternocleidomastoid muscle. A 62-year-old man with poorly controlled diabetes presented with an induration of the neck and fever. On gray-scale sonography, a part of the sternocleidomastoid muscle appeared swollen and contained irregularly shaped hypoechoic areas. Power Doppler imaging showed increased vascularity in the muscle. Sonographic-guided aspiration confirmed abscesses in the sternocleidomastoid muscle. Surgical drainage was successfully performed along with antibiotic treatment. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:520-523, 2017.