A sufficient stability condition for the standard token passing ring has been "known" since the seminal paper by Kuehn in 1979. However, this condition was derived without formal proof, and the proof seems to be of considerable interest to the research community. In fact, Watson observed that in the performance evaluation of token passing rings, "it is convenient to derive stability conditions ... (without proof)". Our intention is to fill this gap, and to provide a formal proof of the sufficient and necessary stability condition for the token passing ring. In this paper, we present the case when the arrival process to each queue is Poisson but service times and switchover times are generally distributed. We consider in depth a gated l-limited (l≤ ∞) service discipline for each station. We also indicate that the basic steps of our technique can be used to study the stability of some other multiqueue systems. © 1992 J.C. Baltzer AG, Scientific Publishing Company.