Serial histological sections in three planes (frontal, sagittal, and transverse) in four cases of clubfoot in fetuses aborted at 16-20 weeks were studied and compared to identical sections obtained in three normal feet. The talus was deformed, with its neck medially angulated and its head dome shaped. The body of the calcaneus was medially bowed and was tilted and rotated medially underneath the talus, and both the talus and the calcaneum were in plantar flexion. The tilting of the talus and the medial tilting and rotation of the calcaneus accounted for the varus deformity of the hindfoot. The varus and adduction deformity of the heel and midfoot caused the supination seen in clubfoot. The skeletal components of the forefoot were adducted as a result of the medial displacement of the navicular and cuboid. Ligamentous and tendon abnormalities were also observed with increased fibrosis of muscle tissue, which may be an important factor in causation of clubfoot.