In this paper, we propose an adaptive decision feedback space-time equalizer (STE) to cope with the problems of co-channel interference (CCI) and inter-symbol interference (ISI) in wireless communications. Unlike the conventional STE, no training sequence is required for the adaptation of the proposed STE. Our scheme consists of an adaptive decision feedback generalized sidelobe canceller (DFGSC), a blind decision feedback equalizer (DFE) and a channel estimator. Due to the feedback operation, the proposed DFGSC is not only superior to the conventional GSC, but also robust to multipath channel propagation. With the special channel-aided architecture, the proposed blind DFE can reduce the error propagation effect. Simulation results show that the proposed STE is effective in mitigating both CCI and ISI even in severe channel environments.