The paper is dedicated to analyzing the process of transformation of efficiency mechanisms in the circular economy. The authors substantiate that a linear economic model with a focus on results in the form of profit does not meet the values of modern society, the main ones of which are the achievement of universal social and environmental wellbeing. Thus, the purpose of this study is to develop mechanisms for ensuring the efficiency of economic activity in the circular economy, a model that meets current values. To achieve the goal, the following research tasks were formulated and solved: to analyze existing generally accepted criteria for assessing efficiency for their relevance to circular economic models; identify the main features of the transformation of the economic system into a circular model; propose an integral indicator of the economic effect of a circular economic system, taking into account all the features of the functioning of such a system; formulate principles of effective interaction within circular ecosystems. As a result of the study, the authors have concluded that it is the economic integration of enterprises within one closed economic system and their interaction that will ensure comprehensive efficiency.