Fibromatosis colli or sternocleidomastoid tumor of infancy is a condition of benign proliferation of fibrous tissue within the sternocleidomastoid muscle leading to focal or diffuse enlargement of the sternocleidomastoid muscle and is often clinically associated with torticollis. Radiological imaging especially ultrasound, if performed by an expert radiologist plays an important role in differentiating this benign condition from other causes of neck masses in this age group, thereby preventing unnecessary investigations in a neonate and decreasing parent`s anxiety. We hereby, present a case report of a sternomastoid tumor in a two week old neonate diagnosed using high frequency ultrasound, signifying that every physician should be aware of this clinical entity in a neonate and refer them immediately for ultrasound.