A Latin American male and a white female infant who had a cytomegalovirus infection on the first day of life had unilateral optic nerve hypoplasia. A white male infant who had cytomegalovirus isolated at 5 weeks of age had a unilateral partial coloboma of the optic nerve. A 4-month-old black infant with cytomegalovirus infection diagnosed at 2 days of age had a unilateral complete coloboma of the optic nerve associated with microphthalmia. Optic nerve involvement was an important manifestation of this disease.