Many of freshwater lakes are in a bad condition having algal blooms and poor transparency in the lake water after decades of eutrophication. This has caused loss of underwater macrophytes and diversity of animals. According to the European Water Framework Directive, lakes should have a good ecological condition at 2015. However, a majority of the lakes do not live up to these requirements. Therefore lake restorations may be needed. In the lecture, an overview of chemical, biological and physical lake restoration methods and their background will be presented.