Macrocrania (i.e., macrocephaly) is a common manifestation of von Recklinghausen neurofibromatosis (NF-1), occurring in approximately 30% of patients with this disorder. Megalencephaly is the usual basis for NF-1-associated macrocrania, although obstructive hydrocephalus secondary to a brain tumor or cranial vault dysplasia may occur. We describe 2 patients with NF-1 and aqueductal stenosis documented by CT scan. The incidence of aqueductal stenosis among our patients with NF-1 is 1%.