The object of research of this work is the conflict of interests of the parties in the implementation of offset agreements. One of the most problematic places when implementing offset agreements is that a wide variety of sudden events, force majeure circumstances, etc. can take place – phenomena that can’t be described in detail and predicted with acceptable accuracy in full. In addition, the offset contract is a conflict of interest between the seller and the buyer. During the study, the methods of the humanitarian and natural-scientific approach are used, thanks to which the conflict was given a new interpretation. It is considered as a way of interaction of complex systems. It is shown that the conflict is not a synonym for confrontation, but a way to overcome contradictions and limitations, a way of interaction of complex systems is an inevitable, normal phenomenon. Of course, conflict involves struggle, but, above all, conflict involves interaction. It is shown that the conflict can’t be considered as an optimization task, since with equal resources of the parties, the conflict will be terminated due to the complete depletion of both sides, and with unequal resources, the defeat of the weaker side with a probability of one. Also, the conflict can’t be resolved within the framework of the theory of adaptation. A brief comparative analysis of the possibilities of using varieties of Markov processes and the degree of their adequacy to the real processes of supporting offset transactions at different stages is carried out. A mathematical model of the conflict between the parties is proposed. In the model, the process of conflict development is a branched semi-Markov process, the transitional and final probabilities of which depend on the ratio of resources of the parties. In addition, the conflict represents a sequence of concerted actions of the parties and, in fact, is a controllable quasiperiodic process with elements of stochasticity. The resulting winnings of the parties to the conflict are investigated with varieties of their cooperation and rivalry. The proposed model can be used to model the processes of development and implementation of offset programs and the wins of the parties.