Managed care employs two business tools of managed practice that raise important ethical issues: paying physicians in ways that impose conflicts of interest on them; and regulating physicians' clinical judgment, decision making, and behavior. The literature on the clinical ethics of managed care has begun to develop rapidly in the past several years. Professional organizations of physicians have made important contributions to this literature. The statements on ethical issues in managed care of four such organizations are considered here, the American Medical Association, the American College of Physicians, the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics. Three themes common to these statements are identified and critically assessed: the primacy of meeting the medical needs of each individual patient; disclosure of conflicts of interest in how physicians are paid; and opposition to gag orders. The paper concludes with an argument for a basic concept in the clinical ethics of managed care: physicians and institutions as economically disciplined moral co-fiduciaries of populations of patients.