North European Russia is one of the most heavily paludified regions of the world. Mires provide crucial biosphere functions, contain plant resources and enormous peat reserves, hold potential as land resources for forestry and agriculture. They are developed and used in various economic activities. Mires of North European Russia have been actively studied since the early 20th century; integrated studies of mires in Karelia have been carried out by the Mire Ecosystems Laboratory of the Institute of Biology KarRC RAS since 1950 and there has formed the Karelian school of mire science, known both across Russia and abroad. Multifaceted studies by several generations of researchers have produced theoretical and methodological developments and detailed classifications of mires, vegetation, peat types, and peat deposits of the region. Outputs of applied value include the republic’s peat cadasters and recommendations on the use of peatlands in agriculture. To secure the conservation of the high diversity of mire ecosystems in the region a network of both mire-focused and integrated protected areas of various statuses has been established with the scientific substantiation of their designation prepared by the laboratory. Integrated studies within a number of international projects and programs have been implemented during more than 30 years. The article describes the key research results produced by the Karelian school of mire science.