A new kind of anhydrous, transparent, and flexible potassium dihydrogen phosphate (KH2PO4 or KDP)/polyvinyl alcohol (PVA) composite in the form of film (0.10 mm) has been prepared by solution casting technique. KDP is well dispersed in the polymer matrix as observed from the microstructural studies. Frequency and temperature dependent dielectric properties of the composites have been studied with varying KDP concentrations. The PVA/KDP composite films exhibited extraordinarily high relative permittivity e' similar to 430 (80 times higher compared with pure PVA and even higher than KDP) near the percolation threshold (?C = 2.5 wt % KDP) with low dielectric losses (similar to 0.15) at 1 kHz and room temperature. Such flexible, low loss and high dielectric permittivity material has enormous importance for application in devices. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012