Since about the 1980s shrinkage has become a new normality especially for European cities and urban regions. As a consequence of the shrinking process, new dimensions of wastelands appear in the affected cities. Urban planners have to find solutions for these “holes” in the urban fabric and new visions are needed for open spaces. In the last few years, the wilderness concept has emerged in the planning field and it has become a fashionable term, in particular in urban restructuring in eastern Germany. If wilderness is a usable concept for urban restructuring, can wilderness be a new structuring element for urban planning? This article analyzes the mechanisms of formation of wasteland in shrinking cities, and then focuses on related debates in urban planning as well as the debates in urban ecology and nature conservation research. The article concludes by considering different aspects of these debates and the question of which role wilderness can play in shrinking cities is discussed.