This research determined the threshold value of 12 specified offensive odor substances based on the 3 point comparison sensory method. The panelist’s thresholds were calculated by taking the arithmetic, geometric mean, and 50th percentile. Three methods of calculating the odor thresholds from the same data are compared. For 12 odor substances, the panelist’s thresholds were showed logarithmically normal distribution. The 50th percentile was the best method among the three methods of caculating the odor threshold from the 72 panel’s thresholdes. As a result, the threshold values of individual odor substances, including methyl mercaptane, hydrogen sulfide, trimethylamine, and i-valeraldehyde ranged between 0.0001~0.001 ppm, while the values of styrene and ammonia were relatively higher than of other substances at 0.089 ppm and 3.2 ppm, respectively. The threshold values of the 12 specified odor substances were compared in Korea and overseas, which showed that the characteristics of sensory response varied by substance and nation.