Studies on professional development comprehend both personal and professional aspects closely linked to the institutional organizations where it takes place. The multiple factors which may be taken into consideration as far as professional development is considered are closely linked to the history of the profession and to the fact that the latter cannot be considered as an isolated process, but rather as a process which implies a complex network of social interactions. In a research carried out in Portugal in the region of Santarem in the year 1996/1997, the professional development of a group of pre- school teachers was studied. Without neglecting the specific characteristics of the context where they work, I reconstituted, by using the biographical method, both their professional lives and the main factors which determine them. After the analysis, it was possible to observe some important aspects, namely the role played by cooperation networks/ partnerships among these professional. Thus, in this presentation the way these teachers analyse the functioning of these cooperation networks/ partnerships and the way they conceive their role in the management of their training process are presented.