We report on two cases of congenital unilateral anterolateral bowing and focal defect of the tibia associated with ipsilateral polydactyly of the great toe. Computed tomographic examination showed an unusual partial cleft of the tibia at the site of bowing. A long follow-up of one patient showed spontaneous resolution of the bowing without progression to pseudoarthrosis. These anomalies should be considered as a new entity related to the tibial developmental field.