Colorectal cancer is often diagnosed at a later stage in blacks. We wanted to know if racial differences existed in the use of tests for detection of colorectal cancer. A 5% random sample was obtained of all Medicare beneficiaries with Part B coverage, aged 65 years and older and classified as white or black race. The numbers of colonoscopies, flexible sigmoidoscopies, and barium enemas were determined from the Physician/Supplier file. Blacks were 18% less likely to receive colonoscopy and 39% less likely to receive flexible sigmoidoscopy after controlling for age, sex, income, and access to care in a multivariable logistic regression model. Barium enema was not significantly different between the races. Black men had 25% lower use of colonoscopy and 50% decreased use of flexible sigmoidoscopy. Blacks receive less colonoscopy and flexible sigmoidoscopy than whites. Black men are particularly vulnerable to the under-use of these tests.