Biguet, one of the redactors of the French civil code, claims that there isn’t a more useful institute than obsolescence. That this claim is not without its basis testifies the long history of the institute, as well as the fact that the institute of obsolescence is generally accepted in all modern legal orders. Why? Obsolescence has a goal to, above all, establish the interrupted balance between the legal and the actual situation, and all this to secure the peace for the society, legal security and discipline of legal subjects. Of course, in order for this legal institute to complete its complex function as it should, it is necessary for it to be regulated by law in a right way. The legislator, on the other side, cannot be left to himself, but has to receive help from the legal theory. The minimum which is expected from the legal theory, not only because of the right standards, but also because of the more qualitative processing of this problematic in the education in universities, is to clearly indicate the difference between the obsolescence and those institutes with which the students of the basic studies, but also prominent legal theorists, often get confused about, and even sometimes identify it. The goal of this work is to, as much as possible, reveal this problematic. We think that for this purpose the most applying thing is to use the advantages of the analytical and comparative methods, because only that way we can expect that we will fully perceive, perhaps not every single one, but most certainly the most important details.