Recent technical advances in molecular biology and cytogenetics, as well as a more developmental approach to congenital heart disorders (CHDs), have led to considerable progress in our understanding of their pathogenesis, especially of the important causative role of genetic factors. The complex embryology of the heart suggests the involvement of numerous genes, and hence, numerous chromosomal loci, such as the recently identified 22q11, in normal cardiomorphogenesis. In order to identify other loci, the Human Cytogenetics DataBase was searched for all chromosome anomalies associated with CHD. Through the application of several (arbitrary) criteria we have selected associations occurring so frequently that they may not be forfuituous, suggesting assignment of a gene or genes responsible for specific CHDs to certain chromosome regions. The results of this study may be a first step in the detection of specific chromosome defects responsible for CHD, which will be useful in daily patient care and may provide clues for further cytogenetic and molecular studies.