We have karyotyped a total of twelve ependymomas using GTG-banding including seven for which preliminary results have already been published. One case showing hyperdiploid main line with two marker chromosomes was further analyzed by nonisotopic chromosome in situ suppression hybridization. It was shown that the marker chromosomes consisted of 1q, 14q and 1q, and 22q. The possible role of chromosome 22 in ependymomas and the usefulness of fluorescence in situ hybridization for cytogenetic analysis in tumor investigation are discussed.