Monitoring of the environment is an important instrument of water resources effective management, well-timed prevention of harmful pollutant influence and thorough information of the public about the state and tendencies of changes in river basin agrosphere. However, the existing system of monitoring doesn’t fully correspond to international requirements and is one of the main restraining factors of the basin management system development. It is suggested to put into the base of monitoring system of socio-economic-ecological systems river basin the unification of well-known home and international monitoring systems which are reasonable to supplement with additional data of regional character. The system of monitoring of river basin agrosphere resources has been substantiated in the article. The main tasks and structure elements of monitoring system have been defined. It is reasonable to fulfill the monitoring of river basin agrosphere state according to appropriate algorithm which forsees the realization of operation cycle, from definition of information needs to information product using. Then the principal blocks of  monitoring  system of river basin agrosphere to estimate the state of socio-economic-ecological systems are considered to be the following ones: socio-economic-ecological and geology-geomorphological, but to estimate  the state of surface waters – hydrological, climatic and bioecological. It should be mentioned that in the suggested monitoring system of river basin agrosphere state the blocks «Observation» and «Prognostication» are closely interconnected as the prognostication of agrosphere state changes is possible only when sufficient and reliable information about its actual state is available. The problem of information  product using by regional and local authorities, as well as, by basin administration is of peculiar attention in the monitoring system of river basin agrosphere state.