The cytogenetic findings based on G-banding in a pineocytoma detected in a 29-year-old woman are reported. The chromosomal study showed numerical alterations involving chromosomes X, 5, 8, 11, 14, and 22, structural alterations of chromosomes 1, 3, 12, and 22, as well as various markers. Tumors of the pineal region are infrequent, and this is the first report of a pineocytoma studied cytogenetically.