This dissertation analyzes the principle of insignificance under a constitutional perspective and examines the consequences of its application in the current Brazilian scenario. There is a discussion on developments of the theory of the crime, in order to locate the principle in the analytical concept of the crime, so we demonstrate it as a exclusion of typicality in its material dimension. It is a logical principle derived from the principle of minimum intervention in their feature fragmentariedade. The principle on focus has an important interpretative function to serve as an evaluative filter, excluding of criminal law either irrelevant behaviour and or irrelevant results. The criteria established by case law assists the interpreter in fair the application of the principle and meeting the purposes of criminal law.