When a company is part of an agreement there is a risk that one of the collaborators pursues similar business and takes up competition with the partner or chooses to reveal information about their partner to other parties. To avoid this, companies establish a confidentiality agreement that prohibits the parties to reveal any information. Confidentiality agreements that are eternal have become more common in Swedish contract law in commercial relations. As a result, disputes between collaborators have occurred regarding the unreasonable length and validity of the agreement at a later stage. When a confidentiality agreement is considered to be unreasonable, 36 § of the Swedish contract law (AvtL) can be applicable. The paragraph deals with the legitimacy and the opportunities of re-adjustment of the unreasonable contract. The question is, can a confidentiality agreement that is eternally valid in commercial relations be modified with the support of 36 § AvtL? Pacta sunt servanda is an important principle in Swedish contract law and the confidentiality agreement is no exception. Hence, the duty of fulfilling a contractual obligation is important. The 36 § of AvtL can be applied when an obligation can be considered to be unreasonable. Confidentiality agreements in commercial relations that are eternal can be seen as unreasonable if a partner is inferior or if later occurred relations changes the meaning of an agreement. If information is considered to be an industrial secret it should be classified according to Act on the Protection of Business Secrets (FHL). However, when the information is not any longer regarded as an industrial secret, it can be unreasonable to have a eternal confidentiality agreement. An example of this can be a patent that expires after a certain period of time. Hence the confidentiality agreement should be able to modify, with the support of 36 § AvtL.