This study was designed to quantify the amount of airborne endotoxins and microbial DNA downwind from a swine facility. There is reason to believe that endotoxins and microbial DNA are present in dust exhausted from swine barns and that adverse health affects may occur from inhalation of this dust. Ambient air samples, dust extractions, endotoxin analysis and microbial DNA analysis of air were taken directly from outlets, 600m downwind and 2400m upwind of the barn. Concentrations of total dust, endotoxin and microbial DNA 600m downwind from the barn were not statistically different from concentrations 2400m upwind where the air was considered to be a