The Mazda 3, first generation (BK platform), represents a significant entry into the compact car segment, produced globally from 2003 to 2009 and in North America from 2003 to 2007. Known for its engaging driving dynamics, sporty handling, and distinctive styling, the Mazda 3 offered a compelling alternative to its competitors. Available in both sedan and hatchback body styles, it was equipped with robust MZR engines, including the 2.0L LF-DE/LF-VVT and the 2.3L L3-VE, paired with either a 5-speed manual or a 4-speed automatic transmission. This model emphasized Mazda's 'Zoom-Zoom' philosophy, delivering an enjoyable and reliable ownership experience. This comprehensive workshop service repair manual provides detailed information for the North American market (2003-2007) and references global variants. It covers essential maintenance procedures, including scheduled service intervals and fluid specifications, as well as in-depth diagnostic and repair procedures for all major vehicle systems. From engine mechanicals and management to transmission, drivetrain, suspension, brakes, and the electrical system, this manual offers step-by-step guidance for component overhaul and repair. It also includes troubleshooting for common issues, technical specifications, and safety guidelines, making it an indispensable resource for owners and technicians alike.