Inflammation This study aims to selecting of Suitable disposing drilling waste sites produced from oil and gas fields. Khark and Lavan islands in Persian Gulf were selected as case study. In this study, effective and causal criteria of suitable disposing site selection for drilling wastes were selecting and prioritizing by the expert team. Data analysis performed using Analytical Hierarchy Process (AHP) and Fuzzy DEMATEL methods. Results indicated that among the required sub-criterion for selecting the suitable waste disposing site on Khark and Lavan islands, distance from city centers and population per weights (0.220, 0.229), distance from roads per weights (0.170, 0.161), distance from rivers per weights (0.139, 0.137) and distance from the airport per weights (0.106, 0.108) are most important sub-criteria respectively. These mentioned sub-criterions have the greatest impact on the selection of suitable disposing sites on these islans. Fuzzy DEMATEL results indicated the effective criteria is distance from city centers which correspond with the results of hierarchical analysis. The results of spatial analysis indicate that the lands located south of Khark island (site1 and 3) and the central lands of Lavan Island (site1, 2, 3, 4, 5) are very good places to evacuate waste.