Öz
The assigment of a claim in return for an act of giving, doing or not doing is a frequently used legal institution today. The Turkish Code of Obligations regulates only the guarantee liability of the assignor as a speecial regulation regarding the violation of obligation in the assignment of claim. The Code doesn’t regulate any special regulation regarding assignee’s breach of dept in assignment of claim. As a consequence of that, at onerous assignment of a claim, the assignor may use optional right to recission of the contract, subject to the application of the general provisions, in case the assignee causes violation of obligation.In case of withdrawal from the assignment of claim, the question arises as to how the reversal will affect the assignment of claim and how the transfferred claim will return to assignor. In addition to that, the legal nature of the damage that the assignor may claim as a result of rescinding the contract should also be examined. In this context, first of all, this subject was examined in our study. On the other hand, new approaches are being brouhgt to the breach of debt system, with the thought that breach of dept system adopted in the Swiss Code of Obligations, which is basis of the Turkish Code of Obligations, cannot fully meet the needs. Examining the effects of the provisions of the General Draft of the Swiss Code of Obligations (OR 2020) regulated in this context on the contract for the assignment of claim, in comparision with the regulations in force, will shed light on the problems in practice.