Mandibular condyle aplasia is a congenital or acquired malformation, which can be or not associated to some head and neck syndromes. Its treatment involves either a surgical approach or a more conservative treatment with orthopedic functional appliances. This clinical report presents a case of mandibular condyle aplasia treated with a modified KLAMT functional appliance, after a surgical procedure failed to stimulate mandibular condyle remodelling. The successful results presented here, with an orthopedic functional approach, support treatment with functional appliances as an alternative, producing similar results to those reported with surgery. Therefore, functional appliances are proposed as a valid alternative to stimulate mandibular condyle remodelling in patients with mandibular condyle aplasia. Treatment provided at an early age appears to be relevant for a successful result.