The aim of this article is to explore different moments of the historical constitution of sanitary engineering in Argentina as a scientific professional expertise, by detecting actors, institutions, national and international networks and conflicts of interest. To accomplish this we investigated journals of the specialty and other documents, both published and unpublished. On the basis of this material, we were able to reconstruct the beginnings of the profession in Argentina, the first professional organizations and the academic formation of these engineers from the beginning of the 20th century until the 1960s.