Fetal biometry is the measurement of the fetus and various segments of the fetal anatomy. Every part of the fetal anatomy may be imaged, but fetal head, abdomen, and femur measurements are the most commonly used, as well as the crown-rump length in early gestation. These biometric measurements can be used to estimate gestational age and fetal weight, evaluate interval fetal growth, and identify fetuses who are either growth restricted or macrosomic. These measurements may influence antepartum and intrapartum management and may be used to predict peripartum outcomes. Biometry is therefore an integral and valuable element of obstetrical practice.