The installation and operation of instrument/sensor networks has great importance in monitoring the physical environment from local to global scale. Nowadays, such networks comprise vital parts of integrated information systems that are called Environmental Information Systems (EIS). Such systems provide real time monitoring, forecasts and interesting conclusions extracted from the collected data sets that are stored in huge databases. These systems are used as the main source of data for model parameterization and as verification tools for accuracy assessment techniques. This paper comprises a short survey aiming to highlight the significant role of existing Environmental Information Systems (ELIS) consisted of instrument/sensor networks that are used for large-scale monitoring of environmental issues regarding atmospheric and marine environment. The operating principles of these systems, their usefulness, restrictions and their perspectives in the environmental sciences, are studied and described.