In this paper, we investigate the performance of a single-relay cooperative scenario where the source, relay, and destination terminals are equipped with multiple transmit/receive antennas. We particularly focus on the so-called blind amplify- and-forward relaying in which the availability of channel state information at the relay terminal is not required. Through the derivation of pairwise error probability, we quantify analytically the impact of multiple antenna deployment assuming various scenarios which involve relay location and power allocation assumptions imposed on the cooperating nodes.