The question of nullity of law-making resolutions of international organizations is essential not only for the organization itself and its law, but also for the member states, which are the addressees of these resolutions. First, the member states, being obliged to implement certain resolutions, must be certain that they will be implementing an act which is both valid and binding. Second, in order to implement a law-making resolution, states may undertake certain legal or factual actions. Hence the nullity of such a resolution would result in a series of consequences, including the problem of restoring the factual and legal conditions existing before a null and void resolution has been implemented. The complex problem of nullity of law-making resolutions requires the consideration of many issues. First, there is the issue of the cause(s) of nullity, i.e. what types of events would cause the resolution to lose its validity. Second, there is the problem concerning the effects of nullity, i.e. is it possible for a null and void resolution to have legal effects; is it possible to validate null and void resolution? Another issue concerns the applicable procedure for the declaration of nullity. In this context, a new question arises: whether member states or the organization itself have the competence to question the resolution? These issues are at the core of the discussion presented in this article.