Exposures to drugs, chemical and biological agents, therapeutic radiation, and other factors before and after birth can lead to pediatric or adult cardiovascular anomalies. Furthermore, nutritional deficiencies in the perinatal period can cause cardiovascular anomalies. These anomalies may affect heart structure, the conduction system, the myocardium, blood pressure, or cholesterol metabolism. Developmental periods before and after birth are associated with different types of risks. The embryonic period is the critical window of vulnerability for congenital malformations. The fetal period seems to have lifelong effects on coronary heart disease and its precursors. During the weeks immediately after birth, susceptibility to myocardial damage seems to be high. Exposure to cancer chemotherapy or radiotherapy in childhood raises the risk of long-term progressive left ventricular dysfunction and other cardiovascular problems. In childhood and adolescence, use of recreational drugs such as cocaine and tobacco poses cardiovascular dangers as well. Where evidence about environmental exposures is limited, we have included models of disease and other exposures that are suggestive of the potential impact of environmental exposures.