The level of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) concentration in blood of 4 chemists conducting dioxin analysis at a laboratory was estimated. The level of PCDDF/s concentration ranged from 4.48 pg I-TEQ/g-fat to 8.17 pg ITEQ/ g-fat (mean level : 6.19 pg I-TEQ/g-fat, median level : 6.07 pg I-TEQ/g-fat, standard deviation in this study : 1.51 pg I-TEQ/g-fat). The level of PCDD/Fs in bloods of the chemists in this study is not higher compared with other studies in Korea. The portion of PCDFs to the total PCDD/F I-TEQ concentration in this study was found to be over 80%. This is not the case in other countries where the portion of PCDDs to the total TEQ in blood was generally much higher than that of PCDFs. In Korea, the portion of PCDFs to the total PCDD/F I TEQ concentration in food was higher than that of PCDDs. In other countries, the portion of PCDFs was relatively lower. It is considered that the portion of PCDFs in blood has interrelation with that of PCDFs in food in both Korea and other countries.