The aim of this paper is to give an overview of the use of indicators and indices for the evaluation of the status of the marine environment. This procedure represents a new integrated approach, where the coastal marine environment is considered as a complex ecosystem, to be studied in all its components. Recent national and international legislation introduces this new concept of environmental quality, while requiring data and information on parameters which were not evaluated in the past. Until now, monitoring and control programmes for the marine environment focused mainly on the chemical status of coastal waters. However, aspects of the biological quality are fundamental for the description of the ecological status; the need for the development of biological indicators and indices provides a challenge for the scientific and technical community managing the marine environment. Living organisms represent the most appropriate indicators for the environmental quality of a water body, as they integrate biotic and abiotic components through their adaptive response. The available information on the current use of biological indicators and indices are illustrated and suggestions and examples on the Mediterranean sea environment are discussed.

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