McDonald's introduced the advertising slogan “I'm lovin' it” in 2003.
The campaign began internationally in Munich, Germany, in September 2003 and was then rolled out across markets. Its wording used a casual first-person expression intended to connect McDonald's food and experience with personal enjoyment rather than a formal product claim.
The campaign became one of McDonald's longest-running global branding platforms. Its short phrase was paired with the “ba da ba ba ba” musical signature, which helped make the advertising recognizable even when translated or adapted for local markets.
The slogan is often discussed alongside the question of who created the campaign. The global advertising work was developed through the German agency Heye & Partner, while later campaign production involved McDonald's agencies in different markets. The date, however, is clear: the slogan launched in 2003.