Aim: To evaluate the effect of the straight-pull headgear and activator (Andresen type) treatment on the eruption pattern of impacted maxillary canines. Methods: Mesiodistal positional, angular, and vertical changes of impacted canines were evaluated and statistically analyzed in pre- and posttreatment panoramic radiographs of 22 patients (12 treated with combination headgear, 10 treated with an activator). Results: Eruption of the permanent canines in the group treated with straight-pull headgear was significantly more successful (88%) than in the group treated with an activator (62%). Conclusion: Mesiodistal and vertical crown position, as well as angulation of canines, differ significantly between subjects treated with straight-pull headgear or an activator. World J Orthod 2009;10:125–129.