To assess the effects of chronic exposure to combustible and non-combustible tobacco product use, a single site, cross-sectional clinical study was conducted. Three cohorts of healthy males (40/cohort, 35-60 years) were enrolled: long-term smokers and moist snuff consumers (MSC), and non-tobacco consumers (NTC). Select biomarkers of exposure (BioExp) and potential biomarkers of effect (BioEff) indicating oxidative stress, inflammation and metabolomic changes, among others, were investigated (accompanying presentations). Blood biomarkers were measured in subjects abstaining overnight from both food and tobacco. Blood carboxyhemoglobin and thiocyanate were significantly higher in smokers relative to both non-smoking cohorts. Whereas the fasting blood nicotine levels were not significantly different between the tobacco consumers, fasting blood cotinine levels were significantly different among all three cohorts (MSC>smokers>NTC). Urinary BioExp from a 24-hr collection included: total nicotine exposure calculated from nicotine and its nine metabolites (NicEq-T), tobacco-specific nitrosamines (TSNAs), polycyclic aromatic hydrocarbons (PAHs), aromatic amines (AAs), and thiocyanate. MSC had significantly higher 24-hr urine levels (mass/24-hr) of NicEq-T than smokers; NTC had the lowest. Urinary levels of NNAL (metabolite of NNK) were significantly higher in MSC relative to smokers, indicating potentially increased exposure and/or preferential metabolism in MSC. Total NNN urinary levels also were higher in MSC compared to smokers, and the underlying mechanism requires further research. Smokers had significantly higher levels of PAHs, AAs, and thiocyanate than MSC and NTC; no differences observed between MSC and NTC. Among trace metals evaluated, only urinary cadmium levels were significantly higher in smokers compared to MSC and NTC. In summary, combustion-related BioExp (e.g., carboxyhemoglobin, thiocyanate, PAHs) were markedly reduced in the non-smoking cohorts compared to smokers, with levels in MSC resembling those observed in NTC.