provided is an apparatus and method for receiving a differential space - time block code without estimating a channel characteristic using an additional training sequence in a wireless communication system using a plurality of transmission / reception antennas . the apparatus for receiving a differential stbc includes a detector for detecting a symbol from a received differential stbc using a trellis diagram and a viterbi algorithm , a deinterleaver for deinterleaving the detected symbol , and a decoder for decoding a signal deinterleaved by the deinterleaver .