Background & Objectives: One of the major problems in environmental management is disposal of municipal waste. In spite of the presence of different methods for the disposal of municipal waste, landfilling is one of the essential elements in municipal solid waste management system. In order to prevent contamination of water and soil, outbreak of diseases and environmental destruction, selection of an appropriate site for solid waste landfilling have to be made through investigation of environmental properties of the surrounding area. The aim of this study was to select the most suitable site for landfilling of municipal waste in Ardebil city. Methods: In a study appropriate sites for landfilling of solid waste have already been determined in Ardabil by applying GIS and analytical hierarchical process model. After field visit from the designated sites and collection of necessary information, four sites were selected. The four sites were assessed using similarity to ideal alternative method and environmental impact assessment by Leopold matrix. From these four sites the most appropriate one was selected. Results: The results of assessment by two methods showed that prioritizing the sites based on the similarity to ideal alternative method is similar to the result obtained from environmental impact assessment by Leopold matrix. The first priority was given to the first option and the second, fourth, and third alternatives stand in the next priorities. Conclusion: The alternative 1 is the most appropriate site for landfilling of municipal waste in Ardabil. This site is located in 11kilometer in east of Ardabil city in geographical coordinates of 48°25′46.90″east and 38° 16′11.63″north.