The outage probability of a recently proposed relay network with multiple antennas at the relay is analyzed. The relay uses maximal ratio combining to combine the received signals, while it uses maximal ratio transmission for the transmission. It is assumed that the reception at the relay and the destination are corrupted by multiple co-channel interfering signals. Closed-form outage probability expressions are derived when the relay is operated in the amplify-and-forward mode with fixed gain. Both cases of equal power and unequal power interferers are considered.