Developmental heart disorders are the most common of all human birth defects and occur in nearly one percent of the population. Survivors of congenital heart malformations are an increasing population, and it is becoming clear that genetic mutations that cause developmental anomalies may result in cardiac dysfunction later in life. This review highlights the progress in understanding the underlying molecular basis for cardiac formation and how disruption of the intricate steps of cardiogenesis can lead to congenital heart defects. The lessons learned from examining the early steps of heart formation are essential for informing the prevention of malformations and their long-term consequences, as well as for approaches to guide stem cells into cardiac lineages.