Patients with severely hypoplastic mandibles usually require condylar reconstruction. This study aimed to describe costochondral graft (CCG) for condylar reconstruction and report subsequent outcomes of these grafts in young children with Pruzansky/Kaban type IIB and type III mandibular hypoplasia. This study included 4 young children with type IIB and type III hemifacial microsomia treated with CCG to reconstruct the condyle at the Department of Oral and Maxillofacial Surgery in our hospital from March 2008 to March 2014. Radiographic measurements and clinical examinations were conducted. The mean age of patients at operation was 3.8 years, ranging from 2.8 to 5.3 years. The mean follow-up period was 43.5 months, ranging from 23 to 63 months. Functional improvement was observed in all patients. The ribs had grown in all patients to date. Three patients had clinically improved face appearance with no significant chin point deviation and canting of the occlusal plane. Although the other patient had partly improved face appearance compared with preoperative condition, he still showed clinically significant facial asymmetry and chin deviation. Our results showed that condylar reconstruction with CCG is a feasible method in the treatment of type IIB and type III hemifacial microsomia in young children. These results will provide early preliminary suggestions of growth and stability of CCG in patients <5 years.