All organ systems function differently in utero, but none functions more differently than the cardiovascular system. While the overall goal of the cardiovascular system is the delivery of oxygen and nutrients to the tissues in both the developing fetus and adult, there are major anatomical and biochemical differences in place to accomplish this feat in the fetus. The most salient of these differences is a series of anatomical shunts not normally found in adults that are crucial to meeting the unique physiological demands of fetal development. In this chapter, we will discuss the normal anatomy and physiology of the fetal cardiovascular system, including changes that occur immediately after birth. We will also discuss specific adaptations in the fetus that are crucial for oxygen delivery in utero. Finally, we will discuss common fetal cardiovascular conditions, how they present clinically, and how Doppler ultrasonography can be used to detect pathological changes in fetal blood flow.