This paper deals with the regu-lation of unilateral termination of long-term contracts within the fourth edition of the UNIDROIT Principles for commercial international contracts (PICC) of 2016. In particular, the work focuses in two cases. First, the right to terminate the contract for an undefined period (recognized in article 5.1.8 PICC). And second, the proposal —by the members of the Working team that prepared this fourth edition— to include a right to unilateral termination in the case of long-term contracts for a defined period, based on “compelling reasons”.