Invalidation is considered one of the important topics in legal legislation. This is because of the violation of its human rules or components, the instability of transactions, the lack of mutual trust it raises between the parties to the contract or third parties, and its retroactive effects on the contract that is the subject of the dispute. This may achieve absolute or relative invalidity in some comparative legislation as a means of achieving relative balance and restoring balance to the parties of the contract. Therefore, we will try, in this research, to show the cases in which the contract must be ruled as complete invalidity or relative invalidity, while explaining the position of the Iraqi legislation, the judiciary, and the comparative. The research problem revolves around the possibility of adopting the idea of dividing nullity into absolute nullity and relative nullity, which was adopted by most comparative legislations, such as Egyptian law, and which caused confusion in some rulings issued by the Iraqi Federal Court of Cassation regarding the use of the phrase relative nullity, which is contrary to what is customary in legal jurisprudence in Iraqi civil legislation, considering that it proceeded on the theory of nullity of one degree.