Autosomal dominant microcornea with a cataract, previously described in four families, was documented in a seven-generation family. Eighteen family members had microcornea and a cataract, and an additional six had sclerocornea or Peters' anomaly. Most individuals with microcornea had a corneal diameter of less than 11 mm in both meridians, with moderately steep corneal curvatures. The inherited cataract progressed to form a total cataract after visual maturity had been achieved. In the four affected children who had not undergone cataract extraction, the common abnormality was a posterior polar lens opacity. The variability of expressivity of the dominant gene would suggest that the embryological origins of microcornea and sclerocornea are similar.