The article presents results of the analysis of the economic sustainability of Ukrainian machine-building enterprises in the context of new economic systems theory. The theory provides for priori division of the economic systems of all levels into four types based on their limitations in space and time – in this way object, environment, process and project systems are allocated. The author hypothesizes that the level of economic sustainability of the enterprise depends on the mutual balance of its internal subsystems of four types, and therefore may be determined on the basis of this balance measurement. For this purpose the special methods to determine the level of balance of the enterprise as an economic system have been developed. It is based on the index measurement of each type of subsystems by Principal Component Analysis (PCA) method, analytical calculation of the index of their perimetric interaction intensity and on their basis – determination the system balance index of tetrad structure of the enterprise. The results of econometric modeling based on these methods according to the 16 Ukrainian machine-building enterprises for the period of 2004-2015 confirmed the hypothesis and led to the conclusion about the systemic nature of structural imbalances. The obtained results will be the basis for developing recommendations for management aimed at maintaining the parity of subsystems of four types and in turn it will provide the economic sustainability of the enterprise.