The authors presented information on green roofs in the European Union (EU) based on the experience of construction companies in the Netherlands and Poland. The choice of these countries was related to the fact that Dutch land planners are interested in cooperating and sharing their experience with Polish specialists. The article also presents a brief history of the use of green roofs. The technical knowledge (on construction, the design of specialized covers and preparation of the entire system) have been gathered from Dutch companies specializing in plant breeding on green roofs. The authors described the advantages of green roofs and the just cause of financing these projects by the EU. Green roofs relieve some of the load on the sewage systems in cities by absorbing precipitation water. They help preventing the floods after storms and torrents. They reduce the negative consequences of heat islands effect and decrease CO₂ emission. Green roofs can solve problems in the areas of Poland that are exposed to harmful gases. Furthermore, green roofs act as a thermal insulation, thus less energy for winter heating and summer air conditioning (energy efficiency) is being used.