[en] The objective of the paper is twofold. Firstly, we will describe a real case of a transparency mechanism applied to the exclusively peaceful uses of nuclear energy between Argentina and Brazil and how this mechanism has contributed to consolidate the nuclear-free zone in the Latin America and Caribbean Region and also to increase international confidence in the exclusively peaceful nature of the nuclear programs of the two countries. Secondly, we will refer to some potential risks that international efforts towards increasing transparency might face if NWS and other countries do not take concrete steps to strengthen it in their respective nuclear activities. (author)