Abstract: In this paper, we consider opportunistic relaying for cooperative communications when the relay nodes randomly and uniformly distributed in space. In the condition of the path loss and block fading channels, we derive the outage probability of the traditional relaying with opportunistic relaying and the incremental relaying with opportunistic relaying. The numerical simulation results show that, although the random distribution of nodes destroys the expected diversity gain offered by relaying nodes, the opportunistic relaying performs better than the directed communication in overcoming the channel fading.