Electroanalytical chemistry can play a very important role in the protection of our environment. In particular, electrochemical sensors and detectors are very attractive for on-site monitoring of priority pollutants, as well as for addressing other environmental needs. Such devices satisfy many of the requirements for on-site environmental analysis. They are inherently sensitive and selective towards electroactive species, fast and accurate, compact, portable and inexpensive. Such capabilities have already made a significant impact on decentralized clinical analysis. Yet, despite their great potential for environmental monitoring, broad applications of electrochemical sensors for pollution control are still in their infancy. Several electrochemical devices, such as pH- or oxygen electrodes, have been used routinely for years in environmental analysis. Recent advances in electrochemical sensor technology will certainly expand the scope of these devices towards a wide range of organic and inorganic contaminants and will facilitate their role in field analysis. These advances include the introduction of modified- or ultramicroelectrodes, the design of highly selective chemical or biological recognition layers, of molecular devices or sensor arrays, and developments in the areas of microfabrication, computerized instrumentation and flow detectors.