In this report, we consider an outage probability for full-duplex single-input single-output (SISO) system. In the presence of self-interference, we derive a closed-form expression of outage probability. We consider Rayleigh and Rician fading channels for the channel between two nodes and for the self-interference channel, respectively. We evaluate the outage probability based on different K factor and signal to interference plus noise power ratio (SINR). We show that outage probability increases as the value of K increases, because the larger value of K is equivalent to the larger LOS component of self-interference power. We also show that active cancellation has better performance in terms of outage probability than passive cancellation. Moreover, we show that our closed-form expression of outage probability matches with the simulation results.