The significance of the binomial "ethics" and "public health" is firstly described. Several definitions are given. A few characteristics making bioethics (concerning mainly individuals) different from ethics in public health (concerning populations) are described. The authors point out how bioethics has been investigated more deeply than public health ethics. Synergy between the two is desirable and efforts should be made in order to promote integration. The importance of research and training in public health ethics and of data exchange with other branches of learning are underlined. A list of national and international institutions dealing with public health ethics is given.