OBJECTIVES: This study was purposed to determine the levels of PCBs and DDE in adipose tissue and serum and to evaluate the relations with factors affecting these levels. METHODS: We analyzed adipose tissues and sera from 52 gynecologic benign disease patients aged 27-78 years, except hormonal diseases such as breast cancer and endometriosis. We also surveyed age, education, occupation, body mass index (BMI), smoking, drinking, number of children, and duration of breastfeeding by questionnaires. Tissue and serum levels of PCBs and DDE were measured using gas chromatography. RESULTS: The median and geometric mean levels of PCBs were 48. 29 ng/g, 56. 78 ng/g for adipose tissue and 4. 67 uc/L, 4. 85 m/L for serum, and those of DDE were 142.89 ng/g, 117.06 ng/g for adipose tissue and l. 75 m/L, 2.09 ua/L for serum, respectively. Adipose tissue and serum levels for DDE showed high correlation (r=0. 310, p=0. 0002), but those of PCBs didn' t (r=0.029, p=0.2582). In analyses of the differences of the means of log transformed adipose tissue and serum PCBs and DDE levels for groups of potential covariates, only adipose tissue DDE levels were significantly associated with number of children (p=0.015), age at first birth (p=0.014) and BMI (p=0.035). In multiple regression analysis, adipose tissue DDE levels were significantly increased with decreasing number of children and increasing age at first birth. CONCLUSIONS: This study suggested that parity and adiposity were associated with levels of DDE in adipose tissue, and adipose tissue is a better biomarker than serum for evaluating the long-term exposure of organochlorines.