Technical Abstract: There is growing concern in the U.S. regarding the emission of volatile organic compounds (VOCs) from farms and their contribution to smog formation near ozone non-attainment areas. The few studies that have measured VOC emissions have identified mixed feed and the exposed silage face as major farm sources. However, there is still much uncertainty in estimating the magnitude of VOC emissions from farms. The objectives of this study were to measure emissions of the most important VOCs emitted from silage; characterize emission patterns; and determine the effects of temperature, air velocity and silage type on emissions. Ethanol, methanol and acetic acid emissions from corn, alfalfa and mixed legume-grass silage were measured using a wind tunnel system and a photoacoustic gas monitor. Measurements under controlled temperature, humidity and air velocity resulted in a common pattern; a rapid decline in emissions during the first two hours followed by a small and steady reduction that lasted up to 24 hours. Silage type, temperature and air flow were important determinants of VOC emissions. These effects should be taken into consideration when predicting emissions and designing measurement approaches. Silage can be an important source of VOC emissions.