Cattle feedlots are major sources of atmospheric NH₃ in the U.S. Unfortunately, NH₃ is a highly reactive compound that is difficult to measure. A micrometeorological system was developed to measure NH₃ gas and NH₄⁺ aerosol fluxes (together known as NH_x flux) from cattle feedlots. The system was composed of a sonic anemometer and chemical NH_x traps composed of an impinger, honeycomb denuder, and filter pack. Gaseous NH₃ and aerosol NH₄⁺ samples were collected and analyzed using ion chromatography. These data were then combined with the sonic anemometer data to compute NH_x flux. Ammonia concentrations were also measured using chemilumnescence techniques. Data were collected during the summer of 2005 at a 30,000-head feedlot in central Kansas. Results will demonstrate the utility of using these techniques for estimating long-term NH_x losses from cattle feedlots.