The article is devoted to theoretical development of termination of civil obligations. The uniqueness of the contract is substantiated as a legal fact, which is explained by the fact that on the one hand it is capable of causing consequences in form of onset, change or termination of civil legal relations or subjective civil rights, legal obligations, and on the other - under the civil contract independent, determined by parties of legal transaction basis for the movement of binding legal relations are fixed, onset of which is associated with onset, change or termination of rights, obligations or even new civil relations between parties of contract. It is suggested that the terms of civil contract establish individual mechanisms for right termination of civil relations and legal models of right-terminating legal facts. The author substantiates that the characteristic feature of contractual obligation is dependence of onset of legal fact in its structure on the lawful will of party (action) of legal transaction or objective circumstances of reality (event) which existence is provided for by legal model of certain legal fact in contract, which, in coincidence with actual circumstances established by such model can lead to achievement of reasonable expectation of parties of legal result and, accordingly, the termination of such obligation. In addition, it has been proved that in practice situations of social conflict that arise between parties to contractual obligations are not exception. Conditions for occurrence of such conflict are onset of legal consequence that was not foreseen by parties to legal transaction as purpose which achievement is the aspiration of parties. The purpose of those facts are termination of legal relations in connection with establishment of defect character of actual or legal side of legal fact at the stage of exercise of right and inability to achieve legal result programmed by parties. The particular attention is paid to such form of termination of contractual obligation as onset of cancellation and delayed condition of legal transaction. It is noted that persons which make legal transaction have the right to provide for termination of subjective civil rights and legal obligations by circumstance concerning which it is not known whether it will come or not (cancellation circumstance).