Aim: To evaluate the effects of orthodontic treatment among individuals with Class II Division 1 malocclusion and severe overbite. Methods: The sample was made up of 70 patients (35 males and 35 females), with an average age of 11.6 years in pretreatment and 14.9 years in posttreatment. One hundred forty lateral cephalograms were obtained and traced by a single investigator. All individuals were treated with the edgewise technique associated with the Kloehn cervical extraoral headgear during the growth spurt, and simultaneously presented ANB > 5 degrees and overbite > 4 mm. Statistical analysis involved t tests for both independent and paired samples and the Spearman correlation test. Results: There were no significant differences between genders regarding the effects of treatment. The cases treated with extraction presented a greater reduction in the SNA angle. On average, all the variables of the study were significantly different when comparing the pretreatment and posttreatment conditions, except for the measurement of the mandibular plane angle (SNGoMe). Conclusion: Correction of severe overbite occurred in virtue of the intrusion of the maxillary and mandibular incisors associated to a reduction of the maxillary prognathism and differential growth of the mandible, as well as dentoalveolar growth. World J Orthod 2008;9:319–328.