In the present study, the fossil bird fauna of the caves of the Hungarian Middle Mountains is examined for evidence in support of the hypothesis that the Carpathian Basin may have served as a faunal refugee during the last Quaternary glacial period. As an introduction, the reasons for the refugee hypothesis, including paleobotanical and glacial theoretical aspects, are discussed. Since the first bird fossils of the cave fauna considered in this paper belong to the Würm I-II, the faunistic conditions of the Riss glacial period are not discussed in detail, The known faunas up to the Würm II are interstadial, which seems to serve only as indirect support for the refugee hypothesis. Paleobotanical evidence, both for and against the hypothesis, is also considered. In conclusion, the abundant cave faunas of all phases of the Würm III are cited as being - at least at the present time - the most convincing argument for the refugee hypothesis. The heterogeneous composition of these faunas permits certain tentative conclusions regarding the faunas of Würm I and II.