The absence of a Romanian legal definition of the concept of nullity of commercial companies arouses a lot of questions. The delimitation of this concept is very important for a correct establishment of its field of application. In other words, are the cases of nullity of commercial companies regulated only by Law no. 31/1990 or by the provisions of common law as well?Started from the fact that the nullity is not considered by the legislator a simple sanction applicable to the juridical acts but it affects directly the existence of the company and becomes a means to sanction the creation of a legal person by disregarding the imperative legal provisions, we analyzed firstly the Romanian (II) and the EU legal provisions regarding the nullity of commercial companies. The elements of this analyze helped us to qualify the nullity of commercial companies and its effect (III). Finally, through the conclusion formulated we hope to call the attention on the fact that a company, even created through the non-observance of the legal rules, can be viable from economic point of view and it is senseless to make it disappearance.