Increasingly widespread adoption of health information technology tools in clinical care increases interest in ethical and legal issues related to the use of these tools for public health and the effects of these uses on the clinician-patient relationship. It is argued that patients, clinicians, and society have generally uncontroversial duties to support civil society's public health mission, information technology supports this mission, and the effects of automated and computerized public health surveillance are likely to have little if any effect on the clinician-patient relationship. It is also suggested, nevertheless, that electronic public health surveillance raises interesting and important ethical issues, some of which can be addressed if not resolved by empirical research, especially regarding patient preferences about secondary use of health data and their moral obligation to contribute to population- based health.