The article investigates the legal nature of these legal categories as recognize and challenge the law in the system of civil law contracts. Reveals the scientific views of the legal profession to recognize the nature of law and challenge the law, defined in common law phenomena and data are allocated their specific characteristics. Grounded in contract law Ukraine challenge civil right or interest is actually impossible, and therefore can not be the basis of protection or the protection of property rights of the parties. The study ofjudicial practice and legal positions of the Supreme Court of Ukraine arguments referring to the category of non-recognition grounds for the protection of property rights of the parties in contract law.