In 22 fetuses, three-dimensional reconstruction was performed on the basis of T2-weighted magnetic resonance (MR) data sets by using a surface-rendering technique. Fetuses and uteroplacental units were segmented manually; volumes were calculated automatically. Three-dimensional reconstruction and volumetry of the fetus and uteroplacental unit are feasible with MR data sets. MR estimates correlated closely with ultrasonographic fetal biometric estimates and birth weight.