The Cobalt sulfide (CoS) nano-particles were synthesized using microwave assisted route. Powder XRD exhibited mixed phase of Co3S4 and CoS. The average crystallite size is found to be 58.28 nm from the Scherrer's formula and 54.41 nm from the Williamson and Hall (W-H) method. Rod like morphology is observed in nano-particles by HRTEM. The EDAX spectrum confirmed the presence of cobalt and sulphur. The impedance spectra were recorded in the range from 10 Hz to 10 MHz at various temperatures from 323 K to 373 K. The complex impedance spectra, i.e., Nyquist plots, were composed of two semicircles indicating the presence of grain and grain boundary contributions of nanoparticles. From the Jonscher's power law plots the Correlation Barrier Hopping (CBH) mechanism was found to prevailing for conduction in CoS nanoparticles. The electrical modulus spectroscopy suggested the temperature dependant relaxation process within CoS Nanoparticles. The results are discussed. (C) 2017 Elsevier Ltd. All rights reserved.