Abstract: In this study, the amount of greenhouse gases emission of some important factors was calculated using life cycle assessment. Sample was 85 dairy farms that were selected by simple random sampling method in 2007. Results showed that electricity and diesel used are the most effective parameters on greenhouse gases emissions in dairy farms, respectively and the other effective parameters are the number of other cattle, the distance of food transferring, cows manure, the No. of calves and dairy cows. It is recommended that the policy makers use some methods like environmental taxes, improving management and carbon sequestration to reduce these kinds of costs. This study results could help policy makers to decide better with considering to effective factors.