We present three cases of hemifacial hypoplasia associated with hypomelanosis of Ito. The facial deformity is often severe with marked soft tissue shortage and underlying skeletal hypoplasia posing difficulty in reconstruction. The external ear is relatively uninvolved, although a degree of hypoplasia is usually present. The hallmark of hypomelanosis of Ito is linear depigmentation of skin often associated with asymmetric abnormalities. It is a heterogenous disorder due to chromosomal mosaicism, but cytogenetic confirmation of the diagnosis may be difficult. The relationship between mosaicism and anatomical asymmetry is discussed.