McDonald's launched “I'm Lovin' It” globally in 2003 as its best-known modern advertising tagline.
The campaign began in Munich, Germany, in September 2003, and McDonald's rolled it out internationally with advertising, music, and the familiar “ba da ba ba ba” mnemonic. The phrase was intended to express enjoyment and an upbeat, contemporary attitude rather than describe a specific product.
The campaign replaced a sequence of earlier McDonald's slogans, including “You Deserve a Break Today,” which had been used prominently in the United States. The new line was adapted across markets while remaining recognizable in English.
People sometimes attribute the campaign entirely to a celebrity performer because Justin Timberlake appeared in an early music video connected with it. The slogan itself, however, is McDonald's brand line, not the title of a particular menu item.