The hearts from two live-born full-term infants with nonmosaic trisomy 9 (one complete trisomy 9, one partial trisomy 9) were studied after death. Both demonstrated conal and valvular anomalies associated with ventricular septal defects. These specific malformations are discussed in relation to published cases of trisomy 9 and the cardiac defects of other autosomal trisomies (13, 18, and 21).