The subject of the article is professional secrecy in practicing the legal profession in American law, with the indication of some differences resulting from separate laws of different states, and in the European Union – taking into account a few exemplary countries. Its sources were described – both legal and ethical, as well as the definition and construction. Confidentiality has been included in the objective and subjective aspect, taking into account different views in the doctrine as to its scope. Bearing in mind the basic right from which professional secrets derive – the right to privacy – the article also includes some of its aspects related to confidentiality.