Al/Poly (methyl methacrylate) (PMMA)/p-Si organic Schottky devices were fabricated on a p-Si semiconductor wafer by spin coating of PMMA solution. Dielectric properties of the Al/Poly (methyl methacrylate) (PMMA)/p-Si structure have been studied using temperature-dependent admittance-voltage (C/G-V) measurements at temperatures below 300 K temperature at 1MHz. The temperature-dependent real and imaginary parts of the dielectric constant (epsilon', epsilon '') and of the electric modulus (M', M '') as well as the ac electrical conductivity (sigma(AC),) of structure were obtained using C and G data. Experimental results show that the epsilon', epsilon '', sigma(AC), loss tangent (tan delta), M' and M '' values were strong functions of the temperature and the applied bias voltage. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.