Congenital torticollis, or wryneck, is caused by fibromatosis within the sternocleidomastoid muscle. It may invlove the muscle diffusely, but more often it is localized near the clavicular attachment of the muscle. An osteochondroma is a benign lesion that is often considered to be the most common type of bone tumor and this lesion rarely occurs in the clavicle. We report a case who had congenital muscular torticollis with solitary osteochondroma on the clavicular attachment site of sternocleidomastoid muscle of medial clavicle.