This paper offers performance analysis of decode-and-forward protocol employing selection combining (SC) at the destination. For an arbitrary number of relays, BER for MPSK of the system is investigated in both independent identically distributed (i.i.d) and independent but not identically distributed (i.n.d.) Rayleigh fading channels. A variety of simulations are performed and show that they match exactly with analytic ones. In addition, our results also show that the optimum number of relays depend not only on channel conditions (operating SNR) but also on modulation scheme which we exploit.