Investigations in wheat fields indicated that grass weeds such as wild oat have become resistant to acetolactate synthase inhibitor herbicides (ALS). Therefore, wild oat resistance status to ALS inhibitor herbicides in wheat fields of Shushtar was investigated in 2014 growing season. Fifty and five seed lots of wild oat (plus two susceptible populations) were collected in wheat fields of Shushtar and points were recorded by Global Positioning System (GPS). Screening test carried out with recommended dose of of mesosulfuron-methyl+iodosulfuron-methyl- sodium+mefenpyr-diethyl (18 g ai ha-1) and sulfosulfuron (19.95 g ai ha-1). The results of screening test based on ‘R’ ratings system showed that 20 (35.09%) and 48 wild oat populations (84.21%) were resistant to mesosulfuron-methyl+iodosulfuron-methyl- sodium+mefenpyr-diethyl and sulfosulfuron, respectively. Also, investigation of distribution map of the populations indicating resistant populations were more in the center and southwestern of Shushtar. It seems due to the importance of the wheat yield and damage caused by the occurrence of resistant weeds on its yeild,preparing distribution map of herbicide resistant weeds is essential action in integrated weed management in wheat fields.Also, investigation of distribution map of the populations indicating resistant populations were more in the center and southwestern of Shushtar. It seems due to the importance of the wheat yield and damage caused by the occurrence of resistant weeds on its yeild,preparing distribution map of herbicide resistant weeds is essential action in integrated weed management in wheat fields. It seems due to the importance of the wheat yield and damage caused by the occurrence of resistant weeds on its yeild,preparing distribution map of herbicide resistant weeds is essential action in integrated weed management in wheat fields.