In 1993, the Clinical Efficacy Assessment Subcommittee began evaluation of new topics and reevaluation of previous guidelines on common screening tests, which were published in Annals of Internal Medicine between 1988 and 1990 and republished as a collection in 1991 (Eddy DM, ed. Common Screening Tests. Philadelphia: American College of Physicians; 1991). Of the 11 guidelines contained in Common Screening Tests, only 3 (for breast, colon, and cholesterol screening) will be published with new data supporting new recommendations. Dr. Littenberg's analysis of the evidence that has appeared since the publication of the original paper on screening for hypertension (Littenberg B, Garber AM, Sox HC. Screening for Hypertension. Ann Intern Med. 1990; 112:192-202) presents a new format for updating Clinical Efficacy Assessment Project (CEAP) guidelines that have not been altered by new evidence. This “updated guideline” reports on new published studies and its analysis affirms the approved American College of Physicians recommendations of 1990. The Clinical Efficacy Assessment Subcommittee carried out the internal and external review procedures that are used for all CEAP guidelines. The plan is to keep all American College of Physicians guidelines updated in this way on a regular basis. Direct any comments or suggestions to Director, Scientific Policy, American College of Physicians, 6th Street at Race, Philadelphia, PA 19106.