This study focuses on the existence of improper solid waste disposal sites in settlements, and difficulties in assigning functions to these under-utilized areas. By considering this basic problem, a two phased evaluation process is developed which concerns the phases of "physical suitability" and "planning suitability". In this evaluation process, physical suitability criterion takes the first phase and declares land use types compatible with the restrictive factors of solid waste disposal sites and also critically important principles of hard and soft landscape design. There are four main restrictive factors on redevelopment of solid waste disposal sites and three of these four factors decrease with time as organic material in waste decomposes. Hence solid waste disposal sites are going to be in change for approximately 30 years, after the closure. Regarding this natural stabilization process, former solid waste disposal sites should be redeveloped phase by phase in a transition from extensive to intensive land uses. Change estimation is an important technique for detecting land uses compatible with these restrictive factors. However it is problematic to estimate changes for the former disposal sites of Istanbul as they were initially improper disposal sites. Problems regarding to change estimation narrow the range of land uses compatible with restrictive factors. According to physical suitability criterion, land use types compatible with the former solid waste disposal sites of Istanbul are determined as ecological, recreational and commercial land uses. Planning suitability criterion takes the second phase of this evaluation process and declares the new land uses capable of integrating into urban system regarding the case areas of this study. In this phase, an original decision support tool is constituted for making decisions compatible with dynamics of Istanbul. After digitizing the land use data about the interaction regions of solid waste disposal sites in GIS, the data are evaluated inside a decision matrix. Prevalues obtained from decision matrix are analyzed by statistical methods in order to declare suitable new land uses. Undoubtedly, interpretation of statistical results is needed according to landscape planning principles, and they should be suitable to the legal and administrative situations. In the second half of 1990's, owing to the risks posed on environmental health and safety, 5 irregular solid waste disposal sites were reclaimed according to engineering techniques in Istanbul. However, after their reclamations they left nonfunctional, hence selected as the case areas of this study. In this study, ecological, social, economic and total potential values are calculated for each of the solid waste disposal sites by the activation of decision support tool consisting of 21 parameters with their own coefficients. By the evaluation process of physical suitability, new land uses compatible with the internal dynamics of solid waste disposal sites are determined. Provided that critically important design principles are utilized, ecological, recreational and commercial land uses are determined as suitable. Ecological, social and economic potentials calculated by the activation of decision support tool, endorse these assigned land uses. Following the statistical analysis of decision support tool's prevalues through Kruskal Wallis H, Mann Whitney U, and One Way ANOVA tests and further analyses of these statistical results, final results about the potentials of solid waste disposal sites are obtained. According to these results, for new uses, it is necessary to arrange Küçükçekmece, Kemerburgaz and then similar sites of Yakacik and Ümraniye, in the order of importance. Aydinli solid waste disposal site's total potential value is lower than the "limit of acceptability" therefore it is kept separate as a reserve open space. Besides ranking the solid waste disposal sites according to their potentials for opening to new uses, this decision support tool declares about the sustainable use potentials of these sites. Therefore, decisions are made about the transformation of Küçükçekmece disposal site to recreational and commercial multiple use; Kemerburgaz site to ecologically based recreational use; Yakacik site to recreational and commercial multiple use; and Umraniye site to recreational use. This decision support tool is proved to be effective on making decisions about solid waste related problematic sites. Therefore, it is possible to adapt this tool for diverse contaminated sites. By the development of this decision support tool for the entire contaminated sites of Istanbul, it is expected to construct a citywide data base on contaminated sites, hence having positive impact on urban matrix. [ABSTRACT FROM AUTHOR]