Sponsored by the biotechnology company Amgen, the eight-day, 700 mile (1,126 km) race started in San Francisco, winding its way down the California coast to finish in Redondo Beach.

With eight of the twenty European UCI ProTour teams in attendance, the inaugural Tour of California proved to be one of the largest cycling races in the United States since the demise of the Coors Classic in 1988.

Among the professional cyclists in attendance were George Hincapie (Discovery Channel), Floyd Landis (Phonak), Chris Horner and Freddy Rodriguez (Davitamon–Lotto), Bobby Julich and Dave Zabriskie (Team CSC), Levi Leipheimer (Gerolsteiner), and Gilberto Simoni (Saunier Duval–Prodir).

Bay Area resident Levi Leipheimer took the early lead in the Tour and secured the leader's golden jersey by winning the prologue time trial.

Gerolsteiner controlled the race, letting Jean Marc Marino (Crédit Agricole) and Jackson Stewart (Kodakgallery.Com-Sierra Nevada) escape, but keeping the time gap small enough to catch them before the finish.

Another sprint to the finish line, and George Hincapie won his second ToC stage; however, the overall standings remained the same, with Floyd Landis holding on to the gold Leader's jersey.