Technical Abstract: The evaluation of mitigation strategies for dairy farms is complex because strategies that reduce one type or source of emission may increase others. A proper evaluation requires a comprehensive assessment of all important emissions and their interactions. Measurement of emissions from dairy farms is difficult, expensive, and ultimately, time and location specific. The Dairy Gas Emissions Model (DairyGEM) was created as an easy to use tool for estimating dairy farm emissions and evaluating the impact of management on those emissions. The model can be generally applied to a wide range of dairy production systems varying from small grazing-based operations to large confinement feeding operations. To maintain simplicity in use, options for describing the details of a farm are limited, but many of the more important options used in the United States can be represented. Location weather files are only provided for the United States, but the model can be used for other regions of the world where similar production practices are used. The DairyGEM software is provided as an educational aid for individual, workshop, and classroom use in evaluating dairy farm emissions and the effect of management changes on those emissions. The software and further information are available at http://www.ars.usda.gov/Main/docs.htm?docid=21345. The software can be installed and used on computers using a Windows® operating system.