An eight months old child with duplication 3p (p21 leads to 3pter) [karyotype: 46,XX,-6,+t(3;6)(6pter leads to 6q27::3p21 leads to 3pter)] resulting from a maternal balanced translocation (3;6) is described. The major clinical findings include congenital heart defects (several ventricular septal defects, atrial septal defect, patent ductus arteriosus, and double outlet right ventricle), and multiple dysmorphic features, such as brachycephaly, frontal bossing, square shaped face, hypertelorism, epicanthus, short prominent philtrum, and short neck. The motor development is retarded. The size of the duplicated segment of 3p is compared to 12 cases reported in the literature. Although the size of the duplicated segment differs in most of the patients, all show a similar pattern of developmental defects. It appears that the region 3p25 leads to 3pter is responsible for the phenotype of duplication 3p syndrome.