This article reviews electrochemical processes and devices that can contribute to a cleaner environment. Electrochemical processes for treatment of waste water solutions, flue gases and contaminated groundwater and soil are described, as well as improvements of existing electrochemical processes or products in order to minimize their environmental impact. Electrochemical power sources for cleaner generation of electricity in fuel cell power stations and for electrically driven vehicles are also discussed. Finally, the important role of electrochemical sensors for monitoring toxic substances is stressed.