Hemifacial microsomia (HFM) is a complex congenital condition. This review discusses recent research findings which affect all aspects of HFM, and addresses some prevailing misconceptions. Firstly, the broad phenotype is outlined, with an emphasis on the facial anomalies which are important for diagnosis, classification and treatment. The range of HFM anomalies and their possible embryology also account for the varied terms used in the literature. In addition, consideration of causation helps to shape our understanding of HFM as a clinical entity. Aetiology is described with particular emphasis on the involvement of genetic factors, although at present this is largely hypothetical. Finally, the principles of HFM management are reviewed. Attention is given to the integrated planning and team approach necessary to treat such patients. In addition, the possible attributes of new treatments, such as distraction osteogenesis, are highlighted.