Objectives: The principal aim of this study was to compare the concentrations of gaseous pollutants emitted in enclosed pig buildings between different rates of general ventilation and determine the variations in the patterns of gaseous pollutants as affected by ventilation rate. Materials and Methods: The experiment was performed in the growing/finishing room($20.0m{ imes}12.0m{ imes}3.0m$) of a pig confinement building located on the experimental farm of Seoul National University. The conditions of the general ventilation rate for three treatments were 30%($4.12m^3s^{-1}$), 50%($6.87m^3s^{-1}$) and 70%($9.61m^3s^{-1}$). The data presented in the study were collected overa total of 45 days, 15 days for each of the three treatments from March to May 2011. A total of six air samplings were taken at 1.5m above the floor of the pig building. The environmental agents measured in the pig building were ammonia, hydrogen sulfide and odor concentration index for gaseous pollutants with temperature and hydrogen sulfide for thermal factors. Results: There were significant differences in the ammonia and odor concentration index in the pig building among the three general ventilation rate conditions(p<0.05), whereas hydrogen sulfide did not show a significant difference among three conditions of general ventilation rate(p>0.05). As the general ventilation rate applied to the pig building increases, it appears that all the indoor environmental agents measured in this study simultaneously decrease. Conclusions: The gaseous pollutants significantly affected by the general ventilation rate in pig building were ammonia and odor concentration index(p<0.05). However, it was found that hydrogen sulfide and thermal factors, temperature and relative humidity were not influenced significantly by variation in the general ventilation rate.