When a patient has an impacted tooth, the timing of orthodontic treatment, the type of surgical procedure to expose the tooth, the orthodontic mechanics, and the potential problems vary depending on which tooth is impacted and its position in the jaw. This case report describes the successful treatment of a patient with a horizontally impacted mandibular canine. The impacted tooth was surgically exposed and then moved into its normal position in the dental arch, combined with correction of a Class II Division 1 malocclusion. (Am J Orthod Dentofacial Orthop 2010;137:S154-62)