This study focuses on the extent to which American corporations developed "brag ads" during World War II. The researchers examined eight databases that included posters and ads produced during the war. From this collection, 397 corporate-produced ads and 104 corporate-produced posters were identified. The researchers then individually identified whether each ad or poster could be classified as a "brag ad." To this, they used the typology set forth by Fox (1975) to describe boastfulness and false patriotism and the description of blue-sky advertising given by then-Senator Harry Truman. In basic terms, ads and posters were judged to be brag ads if the main intent focused more on promoting the merits of a corporation, product, or service than on encouraging patriotism or support for the war effort. The researchers then grouped the brag ads into the six categories of patriotic advertising identified by the Office of War Information (the nature of our enemies, the nature of our allies, the need to work, the need to fight, the need to sacrifice, and principles America is fighting to defend). Results show that 192 ads could be classified as brag ads, mainly in the category of the need to work. This includes praise ads (where a company publicly celebrated an award it had been presented by either the government or the military in relation to its war production efforts) as well as 126 ads that erroneously asserted a company's product as being a direct factor in helping to win the war. In contrast, the researchers identified only eight brag posters. It must be noted that this study is subjective and has many limitations. However, we hope it provides some insights into the extent of brag advertising during World War II. At the same time, we believe the study has relevance to today, especially as advertising and public relations are increasingly used to persuade about such issues as war-related efforts.