Fetal echocardiography remains the cornerstone for the prenatal diagnosis of congenital heart defects. Prenatal diagnosis enables better pregnancy counseling and improves neonatal outcomes. The introduction of four-dimensional (4D) echocardiography, which adds the element of time to three-dimensional (3D) imaging, has significantly enhanced fetal heart assessment by allowing for dynamic visualization of cardiac function and valve motion. This technology has been shown to improve the accuracy of diagnosing complex congenital heart defects, assist in planning postnatal care, and support parental counseling. However, the use of 3D/4D fetal heart evaluation requires a high level of expertise and advanced equipment. Challenges such as image quality and interpretation may arise, but continuous advancements in imaging techniques and computational algorithms are progressively refining these tools, promising further improvements in prenatal cardiac care. This chapter explores the technological advancements, clinical applications, and implications of 3D/4D fetal echocardiography.