Technical Abstract: Odors from cattle feedlots negatively affect air quality in local communities. The purpose of this study was to identifying key odorants using both analytical (odor activity values, OAV) and gas chromatrography GC-O (olfactometry) techniques, compare odor threshold databases, and track the movement of odors from source to receptor community. Odors emitted from a cattle feedlot were sampled onsite, 250m downwind and 3.2km downwind using both sorbent tubes and denuders. Sorbent tubes were analyzed by both GC/MS and GC/MS/O and key odorants determined using both OAV and GC-O, while denuders were analyzed by ion chromatography. Odor concentrations had a diurnal pattern with early morning and late evening being times of peak concentrations. Volatile fatty acids (VFA) were the most abundant of the major odorants. Odorants above their odor threshold at the feedlot included amines, VFAs, phenol compounds, and indole compounds. Key odorants at the feedlot were VFAs and phenol compounds, but their importance diminished with distance. Indole compounds while not the key odorant at the source increased in dominance downwind from the cattle feedlot. In general, the odorous compounds identified by GC-O and OAV were similar. GC-O was the more sensitive analytical technique and it identified several compounds that may have added to the unpleasantness of the cattle feedlot odor, but its through-put was extremely low limiting its usefulness. Improving field sampling devices and odor threshold concentration databases have the greatest potential to improve our understanding and confidence in evaluating odors.