Congenital heart defects are the most common type of birth defect and contribute the most to infant mortality due to birth defects. This study examined the relationship between several demographic factors and selected congenital heart defects among the unique multiethnic population in Hawaii during 1986-99, using data from a population-based birth defects registry. Rates were significantly higher in 1993-99 than in 1986-92 for transposition of the great arteries and Ebstein's anomaly, and significantly lower for tetralogy of Fallot. Significantly elevated rates were found with maternal age of > or =35 years for ventricular septal defect, atrial septal defect, endocardial cushion defect, and hypoplastic left heart syndrome. When cases with a known chromosomal abnormality were excluded, elevated rates among the older maternal age group remained for ventricular septal defect, atrial septal defect, and hypoplastic left heart syndrome. Whites had significantly higher rates than one or more of the other racial/ethnic groups for Ebstein's anomaly and coarctation of aorta, and significantly lower rates for tetralogy of Fallot, atrial septal defect, pulmonary valve atresia/stenosis, tricuspid valve atresia/stenosis, and anomalous pulmonary venous return. Significantly higher rates were found among males for transposition of great arteries, aortic valve stenosis, and interrupted aortic arch and, among females, for ventricular septal defect, endocardial cushion defect, and anomalous pulmonary venous return. Some of these differences were consistent with the literature while others were not.