LIMAS and Tio1 proposed the term meningeal melanocytoma first time in 1972 to describe a primary melanotic tumor of the leptomeninges with prolonged clinical course and benign histology.Meningeal melanocytoma of the central nervous system is rare and benign primary meningeal melanocytoma (PMM) is more exceptional,and also less usual than the malignant types.2 This rare tumor falls under the subclassification of primary melanocytic lesions in the World Health Organizations classification of central nervous system tumors.3 PMM located in the foramen magnum region is an unusual cause of bulbus medullae and fourth ventricle compression.Here we report a 48-year-old man with a PMM which is located in the foramen magnum inducing supratentorial obstructive hydrocephalus.