This paper reports a Class II, division 2 malocclusion case successfully treated at an early age and in a relatively short period of time using the Trainer for Kids (T4K), a prefabricated functional appliance. Skeletal changes observed in the before and after treatment cephalic radiographs were compared with the expected changes produced by the patient’s natural growth. The functional appliance’s effects resulting in the outcomes observed in this clinical case, as well as the importance of identifying the etiological factors when treating a malocclusion will be discussed. Keywords: Mixed dentition, orthopedics, class II division 2, TK4. J Clin Pediatr Dent 32(4): 325–330, 2008