Diastrophic dwarfism is a skeletal dysplasia that can be identified by ultrasound usually during the second trimester of pregnancy. This severe but non-lethal disorder of the cartilage can be diagnosed earlier using transvaginal sonography (TVS). We present a case of diastrophic dysplasia diagnosed at 13 weeks of gestation by TVS. The early TVS evaluation of the fetal biometric parameters and the accurate study of the morphological features of the fetal long bones and extremities allowed an early diagnosis of this rare pathology that leads to a progressive physical handicap, due mainly to severe kyphoscoliosis and arthropathies. Recently, the routine use of TVS at 11-14 weeks of gestation has permitted an earlier diagnosis to be reached of a great number of congenital anomalies. Patients at risk for skeletal dysplasia could benefit from the enhancements of ultrasound techniques. An early diagnosis of diastrophic dysplasia can be reached at the and of the first trimester of pregnancy, using TVS.