The Health Plan Employer Data and Information Set (HEDIS) is a set of performance measures used to assess the quality of care delivered in managed care plans. Chlamydia screening among young women is one new measure recently adopted by the National Committee for Quality Assurance for inclusion in HEDIS. An essential criterion for new measures is that the clinical intervention is beneficial to health and cost-effective. The study seeks to assess the health benefits and cost-effectiveness of chlamydia screening among young women. Articles addressing the epidemiology of chlamydia infection, its health consequences, and the benefits, problems and cost-effectiveness of chlamydia screening were reviewed. The authors conclude that the National Committee for Quality Assurance's recent adoption of the measure for chlamydia screening among young women into the formal HEDIS measurement set is justifiable from a health benefit standpoint and from a cost-effectiveness standpoint.