The necessity of committment to the obligation is one of the importantcontractual principles, but its strict performance is against the equity andjustice, for example in the case that contract or its purpose is frustrated.

All off legal regimes (Systems), for resolving this conflict have presentedsome justifications in the context (framework) of special legal institutions:for example in shariah under the discussion of impossibility (Taazzor) andin french and Iranian law under the section of force majeure and in Englishlaw under the section of frustration.

This research is going to consider the concept and conditions of the legalinstitution of frustration in english law at the first, and then compare thatwith the similar institution such as theory of non- prediction, Taassor (hardship) and force majeure and finally will study their nature and theireconsequences.

In spite of the similarities of this institution with force majeure andTeazzor (impossibility), There are major differences too. Any of theseinstitutions and theories resolve some of the problems of conflict in itself.

The combination and exploiting of the advantages of these threeinstitutions can help to the development of the purposes of Iranianjudiciary system for fulfilling justice.