To study about the law of “hardship”. The hardship is a situation in which the disadvantaged party still has ability in exercising under a contract, but there is an event occurred after the conclusion of the contract was made. As a consequence, the disadvantaged party must pay too much debt or the other party may excessively receive the payment. This causes an unfair condition to both parties if they still oblige to follow with the unfair conditions. Therefore, this thesis will focus on Civil and Common law rules, the Principles of European Contract Law and the UNIDROIT Principles of International Commercial Contracts about hardship which principles have been applied or have been stated. After the research, it is found that, in Thailand, the Civil and Commercial Code states only force majeure provision but not for the hardship; therefore, if there is any problem relating to the hardship or the disadvantaged party is unable to exercise his/her right under the contract due to the substantive changes after the contract was made. The disadvantaged party has to pay much more than they ought to because the hardship is not stated in the Civil and Commercial Code. As a result, the parties will have no right to renegotiate the contract or terminate the contract. As a result, I would recommend that we should propose to amend the Civil and Commercial Code by adding the “hardship” provision clearly, so that when there is a problem regarding the hardship, the parties will have the specific provision to resolve such problem.
