A 5-month-old boy with hypomelanosis of Ito was studied. Lesions presented as bizarre, hypopigmented whorls and streaks. Histologic studies showed that the hypopigmented areas contained normal melanocytes with decreased content of intracellular melanin. A review of the literature revealed the disease to be a discrete entity of hypopigmentation associated with a high percentage of central nervous system abnormalities, particularly seizure disorders and mental retardation.