Market competition and the rise of managed care are transforming the healthcare system from a physician-dominated cottage industry into a manager-dominated corporate enterprise, The managed care revolution is also undermining the safeguards offered by medical ethics and raising serious public concerns. These: trends highlight the growing importance of ethical standards for managers. The most comprehensive ethical guidance for health service managers is contained in. the American College of Healthcare Executives' (ACHE) Code of Ethics. An analysis of the ACHE Code suggests that it does not adequately address several ethical concerns associated with managed care. The ACHE may wish to develop a supplemental statement regarding ethical issues in managed care. A supplemental statement that provides more specific guidance in the areas of financial incentives to reduce utilization, social mission, consumer/patient information, and the health service manager's responsibility to patients could be extremely valuable in today's complex and rapidly changing environment. More specific ethical guidelines would not ensure individual or organizational compliance. However they would provide professional standards that could guide decision making and help managers evaluate performance in managed care settings.