The problem of smart sustainable cities has appeared in the modern research literature relatively recently as a result of the integration of two areas of research - sustainable development and smart cities. However, as the analysis shows, such integration has complicated the understanding of both smartness and sustainability of cities and has posed a new challenge for researchers, namely, to form a monitoring and evaluation approach that would include both dimensions. This article briefly examines the factors that influenced the emergence and development of the concept of smart sustainable cities, defines a smart sustainable city phenomenon, determines the directions of its research and based on the identification of the main problems of monitoring and evaluation of smart sustainable cities, formulates a new approach to monitoring