Celebrities often promote cancer screening by relating personal anecdotes about their own diagnosis or that of a loved one. We used data obtained from a random-digit dialing survey conducted in the United States from December 2001 through July 2002 to examine the extent to which adults of screening age without a history of cancer had seen or heard or been influenced by celebrity endorsements of screening mammography, prostate-specific antigen (PSA) testing, or sigmoidoscopy or colonoscopy. The survey response rate was 72% among those known to be eligible and 51% among potentially eligible people accounting for those who could not be contacted. A total of 360 women aged 40 years or older and 140 men aged 50 years or older participated in the survey. Most respondents reported they "had seen or heard a celebrity talk about" mammography (73% of women aged 40 years or older), PSA testing (63% of men aged 50 years or older), or sigmoidoscopy or colonoscopy (52% of adults aged 50 years or older). At least one-fourth of respondents who had seen or heard a celebrity endorsement said that the endorsement made them more likely to undergo mammography (25%), PSA testing (31%), or sigmoidoscopy or colonoscopy (37%).