In October 2019, a heated tobacco product (HTP) IQOS debuted in the United States. This study examined young adults' attention and cognitions in response to an IQOS ad that carried two mandated textual health warnings (Surgeon General's warning and nicotine warning), and how their vaping and smoking status may interact with attention patterns to affect attitude and intention to use IQOS. In November 2019, college students (N = 164) viewed IQOS' first U.S. magazine ad and two distractor ads. Viewing patterns were recorded with eye-tracking. Masked recall and aided recognition, attitude and intention towards IQOS use were later assessed with self-report. Ordinary Least Squares (OLS) regressions and moderated mediation analyses examined the associations between visual attention and viewers' cognitions about IQOS use. Promotional content attracted significantly more attention compared to the warnings. Attention to the Surgeon General's warning but not to the nicotine warning was associated with recall and recognition of the warning's content. For ever-vapers, greater attention allocation to the promotional content in the IQOS ad was associated with more favorable attitude toward IQOS use, which was in turn positively associated with intention to use IQOS. Attention allocation to the warnings did not affect attitude or intentions, regardless of tobacco use status. The results revealed the effects of IQOS promotional content overshadowed the two health warnings in influencing young people's attitude and intention to use IQOS. Young adults who vaped were more vulnerable to HTP advertising with respect to future use and vaping may be a gateway to HTP use. This is the first eye-tracking study examining attention and cognitions associated with the new IQOS ad exposure among young adults. Promotional content in the ad attracted significantly more attention than the two warnings combined. Attention to the Surgeon General's warning but not to the nicotine warning was associated with recall and recognition of the warning's content. Greater attention allocation to the promotional content led to a more favorable attitude toward IQOS use which was associated with increased intention to use IQOS for ever-vapers. However, greater attention allocation to the warnings did not affect attitude or intentions to use IQOS.