The objective of this study was to measure the long-term odor emissions and corresponding concentrations and emissions of 20 odorous volatile organic compounds (VOCs). This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). Odor and odorous gas measurements at four NAEMS sites, including dairy barns in Wisconsin (WI5B) and Indiana (IN5B), a swine finisher barn in Indiana (IN3B), and swine gestation and farrowing barns in Iowa (IA4B), were conducted from November 2007 to May 2009. The odorous gas samples were collected every two weeks using sorbent tubes (samples were collected twice each season of the year, with the exception of spring 2009 when samples were collected three times) and analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). In this article, we summarize the measured gas concentrations and emissions of the 20 target VOCs from each of the four sites. The average total odorous VOC concentrations for the entire sampling period were 276, 96.9, 1413 and 394 μg dsm-3 for WI5B, IN5B, IN3B, and IA4B, respectively. For the swine sites, the highest seasonal average total odorous VOC concentrations for each barn were observed during spring (1890 μg dsm-3 for IN3B and 458 μg dsm-3 for IA4B). For the dairy sites, the highest seasonal average total odorous VOC concentrations were observed in winter at WI5B (446 μg dsm-3) and in summer at IN5B (129 μg dsm-3). The average total emission rates for the 20 odorous VOCs were 290 mg h-1 AU-1 (WI5B), 36.0 mg h-1 AU-1 (IN5B), 743 mg h-1 AU-1 (IN3B), 33.9 mg h-1 AU-1 (IA4B swine gestation barns), and 91.7 mg h-1 AU-1 (IA4B swine farrowing room). The average seasonal total odorous VOC emission rates were highest during summer at WI5B (805 mg h-1 AU-1), IN5B (121 mg h-1 AU-1), and IN3B (1250 mg h-1 AU-1) and during spring at IA4B (95.8 mg h-1 AU-1). The emissions of specific VOCs varied between seasons, sites, and species. To date, this is the most comprehensive VOC measurement survey of odorous compound emission rates from commercial livestock buildings.