Overexpression of Aurora B kinase, which regulates cell progression through mitosis and cytokinesis, has been shown to be associated with higher-grade tumors and shortened survival in astrocytomas. Aurora B expression was evaluated by immunohistochemistry in 32 ependymomas, 10 anaplastic ependymomas, 16 myxopapillary ependymomas, and 9 subependymomas. Aurora B expression was identified in 20 (62.5%) ependymomas, 5 (50%) anaplastic ependymomas, 1 (6.3%) myxopapillary ependymoma, and no subependymomas. The association between Aurora B expression and World Health Organization grade II/III tumors was statistically significant (P<0.0001). There was no difference in the level of Aurora B expression between ependymomas and anaplastic ependymomas. Aurora B expression was not associated with patient age, sex, tumor location, tumor recurrence, or death from tumor. In contrast to astrocytomas, elevated Aurora B expression in higher-grade ependymomas does not seem to correlate with clinical course, although it may be a potential target of Aurora kinase inhibitors.