Abstract: In order to investigate the influence of Canadian Intense smoking regime (HCI) on the deliveries of tar, nicotine (nic) and carbon monoxide (CO) in mainstream cigarette smoke, a collaborative study involving 18 smoking machines in 12 laboratories were carried out by smoking 10 cigarette samples under ISO and HCI smoking regimes respectively. The results demonstrated that:1) The deliveries of total particulate matters (TPM), tar, nic, CO, and moisture content under HCI smoking regime were much more higher than those under ISO smoking regime, and the ratios of HCI and ISO deliveries of the same components increased with the decrease of tar delivery determined under ISO regime. 2) The ratios of HCI and ISO deliveries of tar, nic and CO were similar, TPM ratio was slightly higher, while the moisture content significantly raised under HCI regime. 3) The ratios of HCI and ISO deliveries of tar, nic and CO augmented with the increase of ventilation rate of cigarette filter. 4) Comparing with rotary smoking machine, linear smoking machine gave higher tar delivery, lower CO delivery, and similar nicotine delivery. 5) The determined results for 1R5F and CM6 in this study demonstrated better agreement with their reference values and the results by relevant international collaborative studies.