Nitrogen fertilizer production and use contribute to the increase in greenhouse gas (GHG) emissions. GHGs due to nitrogen (N) fertilizer use can be reduced to a certain extent with legume agriculture. This study was conducted to estimate the amount of N produced by biological N fixation (BNF) in legumes grown in Türkiye, the amount of synthetic N fertilizer corresponding to this amount of N, and the global GHG emission equivalent of the production, transport, and use of this fertilizer in the field. Firstly, the amount of N fixed by BNF in a year in legume cultivation areas in Türkiye was calculated. Then, the GHG equivalents emitted during the production, transport, and application in the field of synthetic N fertilizers, which is the equivalent of N fixed by BNF, were calculated. The total amount of N fixed with BNF in 2022 in Türkiye is 363,354 tons. The total GHGs emissions during the production, transport, and use of N fertilizer equivalent to 363354 t of N fixed by BNF is 2,631,043 tons CO2-eq. In other words, in one year in Türkiye, 2,631,043 tons of CO2-eq GHGs will be reduced thanks to legume agriculture. GHG emissions of the Turkish agricultural sector (total 72.1 Mt CO2-eq) have been reduced by about 3.65% (2.63 Mt CO2-eq). For an economically and environmentally sustainable agriculture, we need to give more importance to the cultivation of pulses.