Skeletal dysplasias are the result of aberration in the growth and development of the skeleton. While they are individually rare, they are important in that they provide an insight into the mechanism of skeletal development. This article offers an approach to the diagnosis of skeletal dysplasias, rather than an exhaustive account of all the possible diagnoses. Dysplastic conditions are suspected on the basis of abnormal stature, disproportion, dysmorphism, or deformity. Diagnosis requires simple measurement of height and calculation of proportionality, combined with a complete physical examination, appropriate radiographs, an investigation of the family pedigree, and occasionally laboratory studies. An accurate diagnosis can usually be made on the basis of these data and a review of descriptive sources. A definitive diagnosis allows the treating physician to project the patient's ultimate height and to prognosticate about likely deformities and the risk of the recurrence of the condition in the family.