We have prepared karyotypes from a malignant fibrous histiocytoma (MFH) of the brain of a 6-year-old girl. Sporadic cases of MFH in the central nervous system have been reported. However, to our knowledge, this is the first central nervous system tumor to be subjected to cytogenetic analysis. The tumor demonstrated a complex karyotype, with a variety of numerical and structural abnormalities. Although no specific cytogenetic abnormality was observed, the karyotype of this case was similar to those reported for adult MFH of soft tissues.