House dust mites play an important role in the pathogenesis of allergic diseases. Many factors may influence mite growth. The presence of mites is related to mean temperature and humidity as well as altitude. The aim of this study was to analyze the mite fauna in 5 regions of western Anatolia, Turkey, that have similar climatic properties with low mean temperature and humidity, but differ in altitude. During the period October-November 2004, house dust was collected from 290 homes in 5 different cities. House dust mites were isolated in 67 (23.1 %) of 290 samples. The family Pyroglyphidae (Astigmata) was present in all positive samples. This study suggests that the selected western Anatolian regions that share similar environmental conditions host similar dust mite populations.