A continuous-time Markov chain model for an asynchronous spread spectrum packet radio network is presented. The network consists of N fully connected nodes and the radios in all nodes are identical. Packets arrive at each node and are retransmitted when lost, both according to Poisson processes with different rates, and packet lengths are exponential in distribution. A simple threshold approximation is used to account for the multiuser interference, and the preamble collision probability at receiving radios to account for the capture effect. The approximate analysis gives results which are very close to those obtained by simulations in most cases. The network stability conditions are discussed and the bistable behavior of the network is demonstrated. Results are given which show the effects on throughput and packet delay performance of the network according to the variations of the network size, the packet retransmission rate, the preamble collision probability at receiving radios, and the threshold value of the radio channel capacity.