Achondroplasia (ACH) is the most common form of chondrodysplasia in humans. This disorder is inherited as an autosomal dominant trait, though most cases are sporadic. Recent advances in molecular biology have revealed its genetic defect in fibroblast growth factor-3 gene. This may introduce a new diagnostic tool and the classification of ACH and related disorders. Recent molecular engineering techniques have made it possible to provide large amounts of the various kinds of biofactors, such as erythropoietin, granulocyte colony stimulating factor and human growth hormone (GH), for clinical use. In fact, GH has been widely used to treat non-GH-deficient forms of short stature, such as Turner's syndrome, skeletal dysplasia, intrauterine growth retardation, chronic illness and idiopathic short stature, with beneficial effects. This may also be introduced into the medical management of ACH.