In this work, we examine the performance of selective-decode and forward (S-DF) relay systems over kappa-mu fading channel condition. We discuss about the probability density function (PDF), system model, and cumulative distribution function (CDF) of kappa-mu distributed envelope and signal to noise ratio (SNR) and the techniques to generate samples that follow kappa-mu distribution. Specifically, we consider the case where the source-to-relay (SR), relay-to-destination (RD) and source-to-destination (SD) link is subject to the independent and identically distributed (i.i.d.) kappa-mu fading. From the simulation results, the enhancement in the symbol error rate (SER) with a stronger line of sight (LOS) component is observed. This shows that S-DF relaying systems can perform well even in the non-fading or LOS conditions. Monte Carlo simulations are conducted for various values of fading parameters and the outcomes closely match with theoretical outcomes which validate the derivations.