Despite its historical contribution to the improvement of health, public health occupies a marginal position in health systems. This lack of correspondence between impact and power is related in part to its scarce recognition as a profession, and in consequence to the lack of recognition of the professionals in the field. The strengthening of the public health profession requires recognising the coherence of their objectives and scientific basis, but it also requires the establishment of mechanisms to guarantee professional competence. Generally, the institutionalisation of these necessary mechanisms to articulate public health objectives into effective professional practice has been lacking. In other words, the so-called professional competencies lacked development in public health. Progress in this strategy calls for the definition of the professional content based on a functional analysis of public health. That is, an analysis of the functions that these professionals must contribute to society and of the specific activities necessary to achieve the desired outcomes. The aim of this work is to stimulate a debate along these lines taking into account the experiences of other countries. The authors propose to reconsider a further reconstruction of public health, based on an analysis of its objectives, functions and competences, in order to grow away from its marginal position, and improve its social function.