This article describes the preparation of polypyrrole-silk composite fabric by in situ chemical polymerization of pyrrole. In situ polymerization process has been optimized by employing Box-Behnken response surface design. The effect of process parameters on surface resistivity of the fabric has been statistically analyzed. Most significant process parameter and interaction effects have been identified. Thermal, electrical, and morphological properties of the composite fabric have been studied. Surface resistivity of the fabric obtained is 636.33 Ω. The fabric composite shows a liner V–I characteristic like an Ohmic conductor. An exponential rise of surface temperature of the fabric is observed by the application of DC voltage across it. Optical microscopic and SEM studies reveal uniform and even coating of polypyrrole on silk surface. FTIR studies indicate a possible chemical interaction between polypyrrole and silk. The polypyrrole-treated composite fabric exhibits enhanced thermal stability as is evidenced from DSC and TGA result. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41336.