Use of remote sensing for monitoring natural processes, engineering objects, and architectural constructions is considered in the article. The main goal of monitoring is revealing changes on early terms and prevention of negative consequences. Particular attention is focused on radar imagery as an innovative monitoring technology. Advantages of the method are presented. Space radar imagery is used to solve a variety of applications, for example, geodynamic research, ice monitoring, etc. Radars installed on aircraft board provide information for biomass and soil cover assessment. Ground-based radar instruments are used for high-precision measurements of engineering deformations. An overview of monitoring experience with radar interferometers for survey of snow cover, bridges and cultural heritage objects is given.