Description: This paper is elaborated from the standpoint of an ethnographer that has conducted research on a Detention and Training Centre for juvenile delinquents. It aims at discussing the possibilities of communication between ethnographic and institutional knowledges at two levels: the methodological and the political. It is argued that only through effective communication will ethnographic knowledge be able to enrich and eventually have a chance of success in transforming institutional knowledge.With regard to the methodological level - and alongside general ethnographic dilemmas - the specific issues at stake here concern the nature of the institution: in Goffman's terms, this is a total institution. This requires that the ethnographer finds his/her place in the constant, symbolic and physical, struggle that takes place between inmates and staff. This struggle is also characterized by a clear age difference between staff and inmates. How is the ethnographer to develop interpretive and behavioural competences that enable communication and don't jeopardize his/her research? How can the ethnographer simultaneously develop satisfactory and lasting relationships with members of two groups that are daily involved in a struggle for power and status?As far as the political level is concerned, the decisive feature is the fact that the Detention and Training Centre is part of a very rigid hierarchy based in the Ministry of Justice. Although the Centre has educational aims, its integration into this military-like chain of command ends up putting the disciplinary and penitentiary procedures and goals clearly above the educational purposes. It can even be said that the rigour of this chain of command, as well as the severeness of disciplinary sanctions that can be taken against members of staff in case they are found guilty of improper conduct, generate an hypochondriac regime filled with intense and pervasive institutional defence mechanisms. In this context, what place is left for the integration of ethnographic knowledge in institutional operation or even for the transformation of institutional knowledge through ethnographic inputs?As such, the paper is informed by two main sources: a corpus of methodological knowledge in ethnography and a corpus of theoretical knowledge in total institutions (more specifically on institutions for juvenile delinquents). With regard to ethnographic methodology, the stress is more on the practical issues of being in the field than on the so-called "crisis of (ethnographic) representation". With regard to the theoretical knowledge on total institutions, the Goffmanian approach is used as an inspiration but complemented by a concern with the wider context in which any total institution operates. Methodology: Ethnographic research conducted over a 10 months period (September 2003 - July 2004) in a Detention and Training Centre ("Centro Educativo") for juvenile delinquents in Porto, Portugal.Fieldnotes were the main mechanism for registering data.Document analysis was also undertaken. Conclusions: This paper hopes to make clear the relevance of communicational issues for ethnographic research. It points out that communication skills are necessary not only at the methodological level in order to establish relationships and create conditions to carry out the research, but also at the political level in case the ethnographer wishes to have a chance of transforming local knowledge (that is, the knowledge of the place where the research was carried out).