The current study tested contextual features (product design, imagery, and use) of e-cigarette advertisements on responses to the mandated U.S. FDA addiction text warning. In a within-subjects experimental design, young adults (aged 18-24) living in California were categorized into those who use e-cigarettes (n = 149), use cigarettes (n = 66), and dual use (n = 204). They provided affective and cognitive responses to the addiction warning and e-cigarette products in advertisements. Cognitive and affective responses overall were moderately strong, and this pattern was generally consistent across product design and imagery. Those who use cigarettes (versus dual use) reported stronger feelings that they learned new information and lower perceptions that e-cigarettes help reduce cigarette consumption. Those who smoke also reported greater worry, discouragement, and perceived health benefits associated with e-cigarettes and lower perception of harmfulness of e-cigarettes than those who dual use, and evaluated the warning lowest on eliciting encouragement to use and feeling e-cigarettes are a healthy alternative to smoking. Few differences emerged between those who use e-cigarettes and dual use or smoke. The varied response patterns by the use group underline the regulatory challenges of developing strong e-cigarette warnings to deter e-cigarette use.