Wireless and power line communication (PLC) technologies form an important aspect of signal processing for communications in smart grids. This paper provides the performance evaluation of a decode-And-forward based dualhop wireless-powerline mixed cooperative system in terms of analytical average bit error rate (BER). The fading in the wireless channel is modeled by the Nakagami- distribution while that in the PLC channel is modeled using the Log-Normal distribution. The analysis involving Log-Normal fading is very complicated; hence, we use the gamma approximation to Log- Normal distribution for our analysis. The additive noise in PLC channel follows Bernoulli-Gaussian distribution. We derive probability density function of end-To-end signal-To-noise ratio of the considered system. A closed-form expression of the average BER of the considered system is computed. We also evaluate the diversity of the considered system. Validity of the derived analytical expressions is closely verified by simulated results. Index Terms- Bernoulli-Gaussian process, bit error rate, decode-And-forward, Log-Normal distribution, Nakagami-fading. © 2016 IEEE.