The article deals with the peculiarities of legal regulation of unilateral refusal to contractual obligations with the alleged delinquency of the contract`s obligation in the European contract law and US trade law. It has been analyzed some civil norms and  commercial law, providing for this kind of unilateral refusal and scientific work in this area. Particular attention is paid to the research criteria for assessing of the alleged delinquency. The alteration for civil law, handed on implementation`s law assurance to the unilateral refusal in view of alleged delinquency of the contract’s obligation has been suggested.