Antenatal diagnosis of unilateral isolated femoral focal deficiency was made at 20 weeks of gestation. The length of the left femur was shorter than the right, and fetal femur length was below the fifth percentile. The proximal femoral focal deficiency was diagnosed. After delivery, the diagnosis was confirmed with skeletal radiographs and magnetic resonance imaging. In the prenatal ultrasonographic examination, the early recognition and exclusion of skeletal dysplasias are important; moreover, treatment plans should be initiated, and valuable information should be provided to the family.