In 1998, the American Cancer Society (ACS) set a challenge goal for the nation to reduce cancer incidence by 25% over the period between 1992 and 2015. This report examines the trends in cancer incidence between 1992 and 2004. Trends were calculated using data on incident malignant cancer cases from the Surveillance, Epidemiology, and End Results (SEER) Registry. Delay-adjusted incidence trends for all cancer sites; all cancer sites without prostate cancer included; all cancer sites stratified by gender, age, and race; and for 20 selected cancer sites are presented. Over the first half of the ACS challenge period, overall cancer incidence rates have declined by about 0.6% per year. The greatest overall declines were observed among men and among those aged 65 years and older. The pace of incidence reduction over the first half of the ACS challenge period was only half that necessary to put us on target to achieve the 25% cancer incidence reduction goal in 2015. New understandings of preventable factors are needed, and new efforts are also needed to better act on our current knowledge about how we can prevent cancer, especially by continuing to reduce tobacco use and beginning to reverse the epidemic of obesity.