The contribution discusses the importance of the Ljubljana Marshes for economic development. The potential and the idea of turning this area into a fertile granary had emerged already in the 18th century. The first attempts to drain the Marshes date back to this period, and the regulation of the river Ljubljanica played an important role. The first attempts were more or less unsuccessful, and the issue of the Ljubljana Marshes was repeatedly under the spotlight. A new, more intensive period emerged in the middle of the 19th century with the establishment of the Main Committee for the Ljubljana Marshes. The Committee was concerned with the process of draining the Marshes and their adaptation to more intensive farming. The Ljubljana Marshes were also important for the city of Ljubljana and later for the Drava Banate. The efforts encompassed various operations such as amelioration or regulation and drainage, water construction, water supply, flood control, and transport infrastructure construction. Financial institutions, especially the Kranjska hranilnica and the Mestna hranilnica ljubljanska savings banks, played a vital role in financing these complex projects during the Austro-Hungarian Empire and in the 1920s. Until World War II, the Drava Banate was intensively involved in the issue of the Ljubljana Marshes. It received financial support from the Hranilnica Dravske banovine savings bank, which offered special, so-called amelioration loans. In addition to the economic potential and financing of projects, the present contribution examines the questions addressing the history of environmental issues. The Ljubljana Marshes are one of the most changed areas, not only in the vicinity of Ljubljana but also in the wider region. The contribution also considers the process of human intervention in nature, which has had long-term consequences.