As a result of the Montreal Protocol, methyl bromide, a major fumigant for the food industry, is facing a mandatory 100 percent production and import phase out. Millers, food processors and fumigators are looking for replacements. Sulfuryl fluoride is one replacement strategy that was recently labeled for the food market. This presentation summarizes research that is underway to compare the effectiveness of sulfuryl fluoride and methyl bromide under real world conditions. In 2005 and 2006, three sulfuryl fluoride and two methyl bromide fumigations have been completed in four different flour mills. Additional fumigations are currently underway in 2006. All life stages (eggs, larvae, pupae, and adults) of two major pest species, Indianmeal moth, Plodia interpunctella (L) and red flour beetle, Tribolium castaneum (Herbst) were used in bioassays exposed during fumigations. Insect monitoring (moth flight and beetle dome traps) was conducted before and after the fumigations to determine the existing pests population and rebound rates. Current results indicate 100% mortality of larval and adult stages of both species for both fumigants. In addition, sulfuryl fluoride had 100% mortality of the pupal stage, but low initial survivorship of the egg stage. The majority (99.3%) of RFB larvae from treated eggs died before the adult stage. Methyl bromide had 100% mortality of IMM pupae. However, there was extremely low RFB survivorship (0.4%) in one facility and 95.4% mortality of IMM eggs in the other.