Globally, the tobacco industry is promoting heated tobacco products. These products may represent a strategy to promote dual use of tobacco products. One product, IQOS from Philip Morris International, is being proposed in the USA for marketing as a less harmful product. The visual design of tobacco products can influence consumers by implying product characteristics. Thus, we sought to test the impact of IQOS packaging designs on cognitive, affective and behavioural intention responses.From existing IQOS packages used globally, we developed three IQOS packages that decreasingly linked the product to the Marlboro brand. In September to October 2018, we assigned participants randomly to one package in an online experiment. All participants (n=954) were US adults reporting current smoking and no colour blindness. The experiment used quota sampling to ensure diversity by gender, sexual orientation, race, ethnicity and education. Measures were informed by the Context of Consumption Framework. To assess differences in ratings, we conducted non-parametric Kruskal-Wallis tests with post hoc comparisons using Dunn's test.We found significant differences in cognitive indicators including appeal (=6.87, p=0.03), uniqueness (=15.68, p<0.01), brand equity-quality (=122.35, p<0.01) and perceived safety compared with other tobacco products (=14.27, p<0.01). Participants rated packages similarly on affective and behavioural intention measures. All were rated low for talking to others about the product and high for interest in trying with a coupon.Linking or separating IQOS products with a well-established cigarette brand changes how adult smokers respond to the product. Regulators should consider the visual design of packaging.