The I-picture starting time distribution of VER MPEG video sources may significantly affect the cell loss characteristics of ATM multiplexers. The authors propose a new connection admission control (CAC) method which can reflect this effect. For CAC, VER MPEG video traffic is modelled as a composite sequence of three subsequences with different effective bandwidths according to their picture coding types. Experimental results show that the proposed method can fully reflect this effect due to the starting time distribution while also improving network utilisation significantly.