In this paper, we investigate the effects of impulsive noise on the DS/SSMA systems using TCM. We obtain the probability of bit error bound of the systems, considering both impulsive noise and Rician fading unavoidable in mobile communication environments. It turns out that we can achieve some coding gain by using TCM under impulsive noise environment at moderate to high signal to noise ratio (SNR). It is observed that the bit error probability is dominated by the background noise variance when the SNR is low and by the tail noise variance when the SNR is high. (C) 1998 Published by Elsevier Science B.V. All rights reserved.