Technical Abstract: Accurate assessment of the impact of management on agricultural emissions requires consideration of many farm components and their interactions. A comprehensive assessment is needed because changes made to reduce one emission type or source may increase another. A new software tool was developed that uses process-level simulation to predict ammonia, hydrogen sulfide, and greenhouse gas emissions from dairy production systems. A partial Life Cycle Assessment is included to determine the farm gate carbon footprint. This educational tool, called the Dairy Gas Emission Model or DairyGEM, can be used to study the effects of management changes on all of the farm major emission sources from feed production to the return of manure back to the land. Education received through these comprehensive evaluations will lead to the development of more sustainable dairy production systems. More information on the model and the DairyGEM software are available on the Internet at http://www.ars.usda.gov/Main/docs.htm?docid=21345.