IQOS entered the U.S. market in October 2019, then received the Food and Drug Administration (FDA)'s modified risk tobacco product authorization (MRTPA) allowing use of "reduced exposure" claims in marketing in July 2020. A May 2021 court decision regarding patent infringement required IQOS' removal from the U.S. market in November 2021. Using 2019-2021 Numerator marketing data, this study characterized ad occurrences and expenditures-including allocation per ad content (headline theme, imagery) and media type and channel-pre- and post-MRTPA; exploratory analyses characterized the post-court to withdrawal period separately. The study period entailed 685 occurrences and $15 451 870 in expenditures. The proportions of occurrences across the three periods (pre-MRTPA, post-MRTPA, and post-court) were 39.3%, 48.8%, and 12.0%, respectively (p < .001); the proportions of expenditures were 8.6%, 30.0%, and 61.5%. Overall, 73.1% of ad occurrences were via online display; 99.6% of expenditures occurred in print. Per occurrences, prominent pre-MRTPA headline themes included "future" (40.2%), "real tobacco" (38.7%), "get IQOS" (35.3%), and "innovation or technology" (20.1%); post-MRTPA, prominent themes included "not burned or heat control" (32.7%), "reduced exposure" (26.4%), and "distinct from e-cigarettes" (20.7%). Visuals mainly depicted the product alone (pre-MRTPA: 86.6%; post-MRTPA: 76.1%), but increasingly featured women (pre-MRTPA: 8.6%; post-MRTPA: 21.5%). The most prominent media channel theme pre-MRTPA was "technology" (19.7%), but post-MRTPA included "women's fashion" (20.4%) and "entertainment or pop culture/gaming" (19.0%). IQOS leveraged MRTPA in ads, continued marketing post-court decision, and targeted key consumer groups (ie, women). Marketing surveillance of products granted MRTPA is needed, domestically and in other countries, to assess its use and impact. Philip Morris (PM) leveraged IQOS' MRTPA from the U.S. FDA, and continued marketing IQOS after its withdrawal from the U.S. market due to a patent-infringement-related court decision. Notably, IQOS marketing increasingly targeted key consumer groups (eg, women). Given IQOS' potential return to the United States, PM's use of FDA's MRTPA to promote IQOS as a risk reduction product in other countries, and FDA's MRTPA for other products, it is crucial to monitor products receiving MRTPA, their marketing, and their population impact, domestically and in other countries.