Due to the decline in agricultural labor force and rapid aging of farmers, agricultural machinery is becoming larger, higher-performance, and diversified. Tractors use diesel combustion in various operations and emit a number of pollutants, which are the primary and secondary sources for particulate matter (PM) and other air pollutants. In this study, an air pollutant emission inventory for tractor was analyzed and compared with the inventory developed by a national agency. Riding tractors were divided into 3 sub-categories based on engine size. In addition, tractor emissions were classified according to the usage time of each operation. Eight air pollutants such as CO, NOx, SOx, TSP, VOC, PM₁₀, PM_2.5 and NH₃ were included in the inventory. Geographic information system (GIS) was used to spatially assign air pollutants variables into 17 provinces and metropolitan cities in the Republic of Korea. The results showed that the total yearly emissions in 2017 were 3,298 Mg/yr, 9,110 Mg/yr, 4 Mg/yr, 567 Mg/yr, 759 Mg/yr, 567 Mg/yr, 522 Mg/yr and 33 Mg/yr for CO, NOx, SOx, TSP, VOC, PM₁₀, PM_2.5 and NH₃ respectively. The results also showed that total pollutant emissions of tractors were increased 8% compared to the emission inventory developed by a national agency.