Abstract: A genetic-algorithm (GA) based on multiuser detection (MUD) is proposed for the antennadiversity-assisted multicarrier code-division multiple-access (MC-CDMA) systems in the frequency-selective fading channel. Two kinds of GA-based individual-selection strategies are investigated with three different cost functions, which are log-likelihood function (LLF), squared error and squared phase error, respectively. Simulation analysis shows that:with the same cost function, the individual-selection strategy based on Pareto optimality criterion has better performance than the linear combing criterion; with the same individual-selection strategy, the cost function based on squared phase error has the better bit error rate (BER) performance and the better near-far resistance performance than those of two other cost functions.