AbstractClinical and postmortem findings of two cases with karyotype: 48, XXX, +18 are presented. In both patients the usual characteristics of trisomy 18 were found. Case 1 was complicated with congenital esophageal atresia, hypoplastic left auricle with external auditory canal atresia, left congenital dislocation of hip, and left club foot. The patient died on the 9th day after birth. Autopsy revealed mitral atresia, aortic stenosis, ventricular septal defect, patent ductus arteriosus, coarctation of aorta, bicuspid aortic and pulmonary valves, patent foramen ovale, and congenital esophageal atresia (type C). Case 2 died on the 8th day after birth. Postmortem examination revealed ventricular septal defect, but there was no other noteworthy malformation. Dermatoglyphic findings were more prominent on the right hand than the left. The severity of malformations may be biased to either the right or the left side.