On of challenging issues in landlord and tenant relationships act 1977 is definition and Nature of good will. Ingredient of this right wasn't determined in this act and therefor there were many discussions about it. Some believe that in the case of rescinding the rent contract, tenant cannot receive his money paid in start of agreement (key money) but others think that at time of evacuation, tenant can demand the key money because only his good will is lost. It seems that the response to this question depends on the analysis of nature of this right. In this article, aforementioned subject with considering related judgment is discussed. Most of courts believe that in the case of rescinding the rent contract, the tenant cannot demand the key money.