In order to survey the resistance of wild oat populations to clodinafop propargyl herbicide, an experimental study was conducted at the Department of Weed Science, Plant Pest and Disease Research Institute greenhouse in 2008. Treatments included 12 wild oat populations suspected of being resistant to clodinafop propargyl and a susceptible biotype collected from Fars Province. A dose-response study was conducted for 13 wild oat populations. In this study, wild oat populations were sprayed during the 2–4 leaves stage using eight doses of clodinafop propargyl including 0 to 16 times the recommended dose (64 g ai ha-1). Biomass and surviving plant measurements were performed four weeks after herbicide application. Results of this study indicated that all suspected populations were resistant to clodinafop propargyl herbicide. The comparison of resistance index on the basis of biomass and surviving plants showed that the W/F-M2/85 population from Marvdasht had the highest level of resistance. This population could preserve over 50% more of both biomass and surviving plant relative to the control at 16 times (1024 g ai ha-1) the recommended dose.