Neurocutaneous melanosis is a rare congenital syndrome characterized by the presence of large or multiple congenital melanocytic nevi and benign or malignant pigment cell tumors of the leptomeninges. The syndrome is thought to represent an error in the morphogenesis of the embryonal neuroectoderm. We review 39 reported cases of neurocutaneous melanosis and propose revised criteria for diagnosis. Most patients with neurocutaneous melanosis presented in the first 2 years of life with neurologic manifestations of increased intracranial pressure, mass lesions, or spinal cord compression. Leptomeningeal melanoma was present in 62% of the cases, but even in the absence of melanoma, symptomatic neurocutaneous melanosis had an extremely poor prognosis. Useful diagnostic procedures include cerebrospinal fluid cytology and magnetic resonance imaging with gadolinium contrast. Patients may be aided by palliative measures such as shunt placement to reduce intracranial pressure. Dermatologists in their follow-up of patients with large or multiple congenital melanocytic nevi should be aware of this condition, to aid in prompt diagnosis and because the treatment of cutaneous lesions may be altered in the presence of symptomatic neurocutaneous melanosis.