Sacramental seal is an institute, which undoubtedly has principal meaning and seriousness in the canonical law. It depends not only on the substance of the confession, which naturally has character of the absolute confidence between the confessor and the penitent, but also on the need to secure the highest level of protection of the sacrament of penance. Considering these reasons, the institute of the sacramental seal has the absolute protection by the canonical law, which is expressed by the prohibition of its breaching; it does not matter, what is the content of the confession. This paper, analysing of this significant institute, is focused not only the area of the canonical law, but also on the appropriate Slovak legal regulation.