Objectives: This study was performed to evaluate the levels of exposure to persistent organochlorine pesticides in pregnant women in Hokkaido. Methods: Whole-blood samples were obtained from 70 pregnant women aged 17 to 39 years in Hokkaido and analyzed to quantify 29 organochlorine pesticides by gas chromatography/negative ion chemical ionization mass spectrometry and gas chromatography/high-resolution mass spectrometry. Results: Among 29 target compounds, 20 were detected in the whole-blood samples. Mirex, Parlar-26, and Parlar-50, which have never been used in Japan, were identified in all samples, as well as 11 compounds that have been used in Japan. Log-transformed concentrations of compounds with detection rates above 60% linearly correlated with each other (p<0.01). p,p ′-DDE exhibited the highest concentration, with a geometric mean of 730 pg/g wet weight. From the results of the Jonckheere-Terpstra trend test, body weight or age was positively associated with the concentrations of several compounds. Conclusions: We detected 22 organochlorine pesticides including pesticides with no history of use in Japan in the whole-blood samples from pregnant women in Hokkaido. Through long-distance transport mechanisms, these pollutants may distribute widely, and further surveillance of human blood, in addition to foods and the environment, should be conducted.