In medicine, classifications are designed to describe accurately and reliably all anatomic and structural components, establish a prognosis, and guide a given treatment. Classifications should be useful in a universal way to facilitate communication between health professionals and to formulate management protocols. In many situations and particularly with craniofacial microsomia, there have been many different classifications that do not achieve this goal. In fact, when there are so many classifications, one can conclude that there is not a clear one that accomplishes all these ends and defines a treatment protocol. It is our intent to present a new classification based on the Pruzansky's classification, later modified by Kaban, to determine treatment protocols based on the degree of osseous deficiency present in the body, ramus, and temporomandibular joint. Different mandibular defects are presented in two patients with craniofacial microsomia type III and IV according to our classification with the corresponding management proposed for each type and adequate functional results.