Poly(3-hexyl thiophene) has been prepared by a chemical oxidation process. The pristine polymer was irradiated with various fluences of (silver (Ag8+)) swift heavy ions viz. 10(10), 10(11), and 10(12) ions/cm(2). All the samples, irradiated and without irradiation, have been characterized by various techniques such as surface electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Ff-IR and UV spectroscopy. The dc conductivity of all the samples has been investigated in 77-300 K. The room temperature conductivity of pristine samples is 2.39 x 10(-8) which increases to 1.65 x 10(-6) Ohm(-1) cm(-1) at the fluence of 10(11) ions/cm(2). The observed conduction mechanism for all the samples could be explained in terms of Mott's variable range hopping model. (C) 2010 Elsevier B.V. All rights reserved.