Hardship occurs when the occurrence of events fundamentally changes the contract balance, either due to an increase in execution costs or due to a decrease in the exchange value that the party receives. In such cases, one of the three effects of hard slope, namely dissolution, termination and adjustment, is considered as a solution.Theory of infertility contract in the sense in which the event without the involvement of the parties, suddenly, after the conclusion of the contract occurs and conditions governing the contract to the time of conclusion of the significantly changed that as a result of these changes, enforcing contracts the purpose of the contract is impossible and in some cases destroyed.Force majeure theory, this means that after an incident of performance contracts to external, uncontrollable and unpredictable, is impossible. But the theory of hardship, this means that the event is unpredictable and out of control Emergency contractual obligations will be difficult.