The McDonald's visual identity campaign beginning in 2003 was called “I'm Lovin' It.”
The phrase appeared in lowercase as a wordmark and became a central part of McDonald's global brand system. Unlike many earlier slogans that were tied strongly to particular U.S. advertising periods, “I'm Lovin' It” was built as an international platform with local executions.
The campaign is sometimes treated as only a jingle. In fact, it included a broader combination of typography, music, advertising, packaging, and restaurant communication. That combination helped McDonald's keep a consistent identity while adapting commercials and promotions for different countries.
The phrase remains closely linked to McDonald's because it functioned as both a verbal slogan and a visual signature. Its 2003 start marks a major transition from a succession of national taglines to a more unified global branding strategy.