Background: Basically, in any contract, the parties estimate their potential profit and loss and then enter into a contract. However, sometimes the circumstances and circumstances of the time of the contract change so much and make the implementation of the contract heavy and costly. In these circumstances, the implementation of the contract is difficult. This study aimed to investigate the difficulty of contract implementation in Iranian Civil code and commerce from an ethical perspective. Conclusion : In jurisprudence, there is a special rule called "invalidity of the whole contract with the excuse of fulfillment in content", which has become one of the general rules of contracts in jurisprudence. This rule implies the concept that if after the conclusion of the contract, the fulfillment of the obligations arising from the contract becomes impossible forever, the implementation of the content of the contract and its obligations is not necessary and the transaction is void. Iranian law deals with this issue in Articles 227 and 229 of the Civil Code, and conditions such as foreignness and the inevitability and unpredictability of the excuse are considered for the realization of the title of excuse for the execution of the contract. The realized excuse, as the case, will cause the contract to be dissolved or its execution to be suspended until the obstacle is removed.
