Numerous studies have shown that tropospheric ozone is the most damaging anthropogenic air pollutant to agricultural production in the United States. With current global economic estimates of ozone-induced crop loss in the billions of dollars, and most projections suggesting that concentrations of this damaging pollutant will continue to increase in the near future, it is vital that plant breeders are able to develop cultivars with improved tolerance to ozone and other sources of oxidative stress. Using free air concentration enrichment (FACE) technology, soybean cultivars can be grown in a realistic field setting under elevated ozone concentrations. At the SoyFACE facility in Champaign, IL we have examined numerous response phenotypes as candidates to quantify plant response, focusing on changes in morphological, agronomic, and seed composition traits. Screening of over 40 soybean cultivars has suggested that genetic variation contributes to response to elevated ozone in soybean. Using this information we selected two soybean cultivars exhibiting differential ozone response from which we developed a 208 member recombinant inbred line (RIL) population. This population is being genotyped using the Universal Soy Linkage Panel (USLP 1.0), and the resulting genome wide linkage map will be used to identify putative QTL related to yield loss, effects on plant growth and development, and changes in seed composition in response to elevated ozone. Any identified QTL will be further investigated to elucidate the genetic mechanisms involved in plant resistance to stress caused by elevated ozone, and provide information to breeders to facilitate the development of soybean cultivars which are better adapted to current and future levels of tropospheric ozone.