The cost of health care continues to be a matter of great concern to purchasers of service. In an effort to control their expenditures, many employers, insur ers, health maintenance organizations, and preferred provider organizations are assessing the effectiveness of their current cost-containment programs and im plementing more stringent approaches where indi cated. To respond to this situation, hospitals must develop effective utilization management programs that are designed to identify and resolve problems before they come to the attention of outside organi zations. Every aspect of the program should be eval uated periodically to assure that it is effective and continues to meet the needs of the hospital, its medical staff, and its patients. This paper describes the factors that make effective utilization management manda tory today and outlines a methodology for assessing effectiveness.