In this paper we propose a congestion control method for interconnecting connectionless MANs with ATM networks which works at the gateway of DQDB. Since connectionless traffic belong to loss sensitive data, they should experience small cell loss rate. Due to the function of congestion control in the gateway, we can prevent the network from overload which not only introduces serious cell loss at remote destination gateway but also lots of undesirable retransmissions and lime delay in the ATM network. It neither needs to modify the slot format of DQDB nor to increase the overhead so the implementation is simple and cost effective. Performance results are also provided to verify the effectiveness.