The purpose of this study was to determine the effects of the pendulum appliance on distalization of maxillary molars and the reciprocal effects on the anchor premolars and maxillary incisors. Initial and follow-up cephalometric radiographs were obtained on 41 subjects (26 girls and 15 boys) who were treated with the pendulum appliance for bilateral distalization of the maxillary first molar teeth, for correction of the Class II molar relationship or for gaining space in the maxillary arch. Dental casts were available on 31 patients. Dental, skeletal, and soft tissue changes were determined. The mean maxillary first molar distalization was 3.37 mm, with a distal tipping of 8.36 degrees. The mean reciprocal mesial movement of the first premolar was 2.55 mm, with a mesial tipping of 1.29 degrees. The maxillary first molar position intruded 0.1 mm, whereas the first premolar extruded 1.7 mm. The transverse width between the mesiobuccal cusps of the first molars increased 1.40 mm. The maxillary second molars were also distalized 2.27 mm, tipped distally 11.99 degrees, and moved buccally 2.33 mm. The effect of distalization on the maxillary third molars was extremely variable. The eruption of maxillary second molars had minimal effect on distalization of first molars. The lower anterior face height increased by 2.79 mm. This increase was greater in patients with higher Frankfort-mandibular plane angle measurements. The pendulum appliance is an effective and reliable method for distalizing maxillary molars, provided the anchor unit is adequately reinforced. Its major advantages are minimal dependence on patient compliance, ease of fabrication, one-time activation, adjustment of the springs if necessary to correct minor transverse and vertical molar positions, and patient-acceptance.