Skeletal dysplasias are heritable connective tissue disorders affecting skeletal morphogenesis and development. They represent a heterogeneous group of genetic disorders with more than 200 different entities being delineated to date. Because of this diversity, the diagnosis of a skeletal dysplasia is usually based on a combination of clinical, radiographic, morphologic, and, in some instances, biochemical and molecular studies. Tremendous advances have been made in the elucidation of the genetic defect of several of these conditions over the past 10 years. This progress has provided us with more insights into the genes controlling normal skeletal development. It also has opened new diagnostic perspectives. For several disorders, identification of the causal gene allows us now to confirm with a molecular test the diagnosis postulated on the basis of clinical, radiographic and/or morphologic studies. It also enables us to establish the diagnosis early in pregnancy. An accurate diagnosis is not only important for proper management of the affected individual but also the cornerstone for adequate genetic counseling.