In this paper, the author offers a discussion of the criminal tax offenses in the area of declaration, regulated in Articles 2, 3, 4 and 5 of Chapter I, Title II of Legislative Decree No. 74/2000 and relating respectively to fraudulent declaration by use of invoices or other documents for non-existent transactions, fraudulent declaration by other artifices, unfaithful declaration and the hypothesis of omitted declaration. These are the most serious offenses, as the declaration represents the moment at which the objective and definitive assumption of tax evasion is realized on the taxpayer's side. Therefore, the insidious conduct of the taxpayer who alters the contents of the declaration, manipulates accounting records or even intentionally fails to fulfill the declaratory obligation is colored with a reprehensible character such as to warrant special attention from the legislature. Through a fascinating interweaving of criminal and tax notions, the objective and subjective constituent elements of the offenses in question will be examined, highlighting the ambiguities of a regulatory text that is sometimes difficult to understand and that has given rise to numerous doctrinal and jurisprudential contrasts, contrasts that have not yet subsided, although more than a decade has passed since the criminal-tax reform.