The aim of the present study was to assess smokers' level of agreement with smoking-related risks and toxic tobacco constituents relative to inclusion of these topics on health warning labels (HWLs). 1000 adult smokers were interviewed between 2012 and 2013 from online consumer panels of adult smokers from each of the three countries: Australia (AU), Canada (CA) and Mexico (MX). Generalized estimating equation models were estimated to compare agreement with smoking-related risks and toxic tobacco constituents. For disease outcomes described on HWLs across all three countries, there were few statistical differences in agreement with health outcomes (e.g. emphysema and heart attack). By contrast, increases in agreement where the HWLs were revised or introduced on HWLs for the first time (e.g. blindness in AU and CA, bladder cancer in CA). Similarly, samples from countries that have specific health content or toxic constituents on HWLs showed higher agreement for that particular disease or toxin than countries without (e.g. higher agreement for gangrene and blindness in AU, higher agreement for bladder cancer and all toxic constituents except nitrosamines and radioactive polonium in CA). Pictorial HWL content is associated with greater awareness of smoking-related risks and toxic tobacco constituents.