The paper reports sonographic prenatal diagnosis of monogenic and chromosomal syndromes (congenital malformations) which are associated with skeletal abnormalities: autosomal recessive syndromes (shortribs--polydactyly, type II; dyssegmental dwarfism, type II; Pen-Shokeir disease type I), autosomal dominant syndromes (Larsen's syndrome, achondroplasia, Schmidt's metaphyseal dysplasia of segregating partial chromosome of 7 long-arm trisomy). All cases were detected in the second trimester; diagnosis of chromosomal diseases employed the amniocentesis. In aborted pregnancies, diagnoses were confirmed at autopsy. Pathognomonic sonographic markers were described for every syndrome; numerous conditions were differentiated from similar syndromes. Genetic counseling identified recurrence risks and offspring prognosis. Potentials of sonographic diagnosis of systemic skeletal dysplasia and a need for a syndrome-oriented approach to prenatal diagnosis are discussed.