OBJECTIVES To understand the impact of U.S. cancer screening guideline information on U.S. cancer screening and cancer detection. METHODS We use an instrumental variables research design to identify the effects of breast, colorectal and prostate cancer screening guideline information on cancer detection. U.S. guidelines specify an age at which screening should begin, implicitly recommending that screening not occur for asymptomatic individuals below that age. We first estimate compliance with guideline information from the difference in age-specific screening rates just below and above the ages at which clinical guidelines recommend that screening begin. We then perform instrumental variables regression analyses to estimate the effect of guideline induced screening on cancer detection. U.S. cancer screening and incidence data (years 2000-2005) are derived from the Behavioral Risk Factor Social Survey, the National Health Interview Survey and the SEER Program. RESULTS Age-specific screening rates from national BRFSS and NHIS survey data indicate that U.S. breast, colorectal and prostate cancer screening in the last year rise by 55%, 88% and 29% precisely at the guideline recommended ages(age 40 for breast cancer and age 50 for colorectal and prostate cancers). Results from instrumental variables analyses indicate that a 1% point increase in screening at the guideline recommended ages leads to an additional case of breast and colorectal cancer detected per 100,000 individuals. The substantial increase in prostate cancer screening did not have an identifiable effect on prostate cancer detection. CONCLUSIONS We used an instrumental variables strategy to identify the impact of guideline information on cancer screening and detection. Guideline information induces substantial increases in breast, colorectal and prostate cancer screening but these changes only lead to increases in breast and colorectal cancer detection. These results suggest that reductions in the use of the PSA test will result in substantial cost savings with minimal reductions in health.