The objective was to provide a systematic review of the literature on greenhouse gas (GHG) emissions from swine operations, with a meta-analysis that integrates results of independent studies. A total of 53 studies that measured GHG emissions from swine operations were included in the analyses. Results showed that the Intergovernmental Panel on Climate Change (IPCC) approaches were effective in estimating the overall CH4 and N2O emission levels from swine operations, but the variation of the measured emissions is not adequately captured. An overestimation by the IPCC approaches for CH4 emissions was observed for swine buildings with pit systems in European studies and the average percentage relative difference (PRD) between the measured and the IPCC values is –21.1%. The observed CH4 emissions from lagoons were lower than the IPCC estimated values and the average PRD is –33.9%. In North American studies the observed N2O emission factors for swine buildings with pit systems were significantly lower than the IPCC default values whereas in European studies they were significantly greater than the IPCC default values. The measured CH4 and N2O emissions were significantly affected by stage of production (P = 0.05 and