Anhydrous proton conductive KHSO4-H3PW12O40 (KIS-WPA) composites were successfully synthesized using mechanochemical treatment. 95KHS.5WPA (mol%) composite, for example, showed very high anhydrous proton conductivity of 1.3 x 10(-2) to 2.4 x 10(-3) S cm(-1) in a temperature range from 160 degrees C to 80 degrees C under ambient pressure. Chemical interactions via ion-exchange and hydrogen bond between KHS and WPA were confirmed from structural studies. Furthermore, the anhydrous proton conductivity of the KHS-WPA composites was well correlated with their estimated hydrogen bonding distance, indicating that reduction of the hydrogen bonding distance in the KHS-WPA composites is significant in the proton hopping to achieve anhydrous high proton conductivity. (C) 2011 Elsevier Ltd. All rights reserved.