Intensive investigations into the utilisation of the geothermal potential of the North German Basin began in the early 1980s. The first production and reinjection tests from/into sandstone reservoirs started in 1982 and led to the commissioning of the first geothermal heating plant for heat supply to a residential area in the town of Waren (Muritz) in 1984. More plants were put into operation in Neubrandenburg, Neustadt-Glewe and Berlin. The use of these sandstone reservoirs for heat storage produced new technical solutions. A precise knowledge of the geological and geochemical conditions forms an essential prerequisite for the successful planning, construction and operation of geothermal plants. This paper describes the geological and geochemical conditions, as well as the technical solutions and practical experience acquired so far. (C) 2003 CNR. Published by Elsevier Ltd. All rights reserved.