This article reviewed selected works on how decision makers (DMs) utilize integrated geographic information system (GIS)/analytical hierarchy process (AHP) tools to analyze land suitability for sanitary landfill sites as part of regional planning. We analyzed the hierarchy process of certain pervious works to facilitate better understanding. The innovative work of Siddiqi et al. in 1996 highlighted the advantages of integrating AHP in GIS software and reviewed some limitations. The present paper explained the background study on multi-criteria decision analysis/aid (MCDA) so-called multi-criteria decision makers (MCDM) in conjunction with the advantages of GIS as a new remedy for utilizing the AHP weights of the decision makers. For this study we often use the term MCDA and MCDM. © (2014) Trans Tech Publications, Switzerland.