The Bhas 42 cell transformation assay (CTA) has been used to complement standard in vitro testing of tobacco products for understanding downstream biological implications of genetic toxicological changes related to tumor promotion. Investigators have typically published CTA results showing tumor promotion by the combustible Kentucky Reference (KY) cigarette 3R4F compared to the lack of tumor promotion from next generation/non-combusted tobacco products. Although it is more relevant to benchmark the tumor promotion activity of new or potentially reduced risk tobacco products with currently marketed cigarette products rather than reference standards, few results/comparisons have been published. In the present study, we used the CTA assay (OECD 231) to determine the tumor promotion potential of four combustible cigarettes, including two leading US market products, Marlboro Gold Pack Box and Newport Box, and two KY cigarettes, 3R4F and 1R6F. Total Particulate Matter (TPM) was collected from the test cigarettes according to Health Canada Intense (HCI) smoking regimen parameters. Based on the preliminary growth assessment assay data, the TPM concentrations selected for testing ranged from 5-125 µg TPM/mL for all four test items. Under the conditions of this assay, all test items were positive in the promotion assay for cell transforming activity, with the lowest effective concentration of each test item ranging from 5 to 25 µg TPM/mL. These data demonstrate that there was little variability among the test item responses, and each product induced a dose-related response in the promotion assay. In summary, two current leading market combustible products yielded tumor promotion activity that was consistent with responses observed for KY cigarettes suggesting that they could be used as combustible cigarette comparators in future Bhas 42 assays.