— In this paper, we introduce a novel Markov Chain (MC) representation aided Minimum Bit Error Rate (MBER) detection method that is applicable to an M-QAM modulated SDM/SDMA uplink system. Compared to the conventional MBER scheme, the proposed MC-MBER scheme is capable of reducing the complexity imposed with the aid of its efficient detection candidate set generation assisted by the Markov chain process. Our performance results demonstrate that the MC-MBER Multi-User Detection (MUD) is capable of reducing the computational complexity by a factor of eight in comparison to the conventional MBER MUD in a rank-deficient system transmitting four 4-QAM uplink substreams with the aid of two receive antennas at the Base Station (BS), while achieving a BER performance comparable to that of the MBER MUD.