This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions. Odor emissions from two animal species (dairy and swine) from four sites with nine barns/rooms (two dairy barns in Wisconsin, two dairy barns and two swine rooms in Indiana, and three swine barns in Iowa) during four cycles (13-week periods) were measured. Odor samples were analyzed in three olfactometry laboratories and no significant difference was found among these laboratories. The highest ambient odor concentrations and barn odor emissions were measured for the Iowa swine site. The most intense odor and the least pleasant odor were also measured for this site. Ambient odor concentrations were the lowest for the Wisconsin dairy site. But the lowest barn odor emission rates were measured for the Indiana dairy site. Significantly higher odor emissions were measured in summer.