Abstract: This study focus is on discussing contracts that are concluded with a defect in one of the elements which may affect its legality and validity, threaten its existence with abolition as well as affecting the parties of the contract and their rights and duties arising from the contract. One of the implications of such a defect in the contract is that the contract may be considered to be null or it is applicable to nullity. Islamic jurisprudence has the same principles on the validity of contracts in terms of the presence of the contract’s entire elements, so as to be legally generated and become effective. In contrast, the presence of any defects in a contract will affect the validity of the contract and may lead to nullity or become a voidable contract. The aims of this study are the definition of nullity and to explain the types of nullity (absolute nullity and relative nullity) and its direct and indirect effects which may lead to invalidity, derogation, conversion, adjustment of the null contract in civil law and Islamic jurisprudence.