This paper is concerned with the geometric decay property of the
stationary probability $\pi(n_1,n_2;i_0,i_1,i_2)$ in two-stage tandem
queueing system $PH/PH/1\rightarrow\/PH/1$. We prove that, under some
conditions, the stationary distribution of the two-stage tandem
queueing system has geometric tails. Furthermore, we obtain the
asymptotic form of the tail.