Pursuant to Articles 2 and 3 of the Protocol No. 1 on the role of national parliaments in the European Union, national parliaments have the right to send reasoned opinions on the compliance of draft European legislative acts with the principle of subsidiarity. The article is aimed at showing a real extent of this new power of national parliaments. In this context, of key importance is defining the notion of 'legislative act', taking particularly into consideration the doubts it raises in relation to acts adopted under special law-making procedure that has not been explicitly specified in the EU establishing treaties. First, the authoress presents the power of parliaments to scrutinize the compliance with the principle of subsidiarity. Then, she describes the system of EU legal acts after the reform introduced by the Treaty of Lisbon. The article also deals with the definition of acts adopted under a special law-making procedure. It also makes a distinction between acts that are declared by the Treaty on the functioning of the EU as subject to be adopted according to special law-making procedure and acts about which there is no such information in the Treaty. An analysis contains all situations where a legal act is adopted by the Council with the consent of, or after the consultation with, the European Parliament, but the provision of the act does not explicitly indicate that that special law making procedure is applied. This fact is of key importance, because the assumption that the lack of such reference results in classification of these acts as not adopted under a special, and the more so - normal - procedure, eliminates them from the category of legislative acts and, therefore, makes it impossible to scrutinize the compliance of the principles of subsidiarity by them. This means that these acts - sometimes of considerable political and economic importance - are excluded from the review of the national parliaments. The analyses provided by the authoress enable us to say that despite of some doubts, legal acts that are not declared as subject to adoption under special or normal law making procedure, are not legislative acts. Hence, national parliaments are not entitled to scrutinize their compliance with the principle of subsidiarity.