Despite doubts about the benefits of colon cancer screening, sigmoidoscopy and fecal occult blood tests are now often performed by clinicians who must then deal with positive test results. The purpose of this literature review is to examine potential strategies for dealing with positive screening test results. If positive results are obtained, current data support the use of colonoscopy as the single most effective diagnostic strategy. Exceptions include situations that reduce the predictive value of the screening test. Several important areas of controversy are highlighted that need to be assessed in subsequent studies.