This paper analyzes the outage probability for amplify-and-forward (AF) and decode-and-forward (DF) cooperative diversity systems with selective combining, for the case of a log-normal Nakagami faded desired signal and log-normal Rayleigh faded co-channel interferers. The outage probability is compared to that of a dual-receive antenna system also with selective combining. The results of this paper show that the proposed cooperative diversity systems can result in a lower outage probability than the corresponding dual-receive antenna system, but only when the relay is located in a particular region of the cell with respect to the destination mobile station location. Moreover, this paper shows that the AF cooperative diversity system is more robust than the DF cooperative diversity system for the composite channel condition and multiple interferers. Copyright © 2010 John Wiley & Sons, Ltd.