To estimate levels of organochlorine residuals in the Japanese population and the contribution of dietary factors to these levels, we determined serum levels of beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) and p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) in 41 volunteers (14 men and 27 women) in a rural area of Northern Japan. These organochlorine levels were measured using gas-chromatography mass-spectrometry. By a self-administered dietary history questionnaire, the usual dietary intake was estimated. Their median levels (range) were as follows: beta-HCH, 0.50 (0.05-1.50); HCB, 0.20 (0.02-0.70); and total DDT (p,p'-DDE + p,p'-DDT), 5.0 (0.9-31.0) ng/ml serum. Levels of p,p'-DDD were detected in only seven subjects (0.05-0.6 ng/ml serum). The beta-HCH levels were increased with rice and milk intakes, but the least squares means were not simply increased according to the quartile of the intakes. Concerning HCB, fish intake showed a borderline significant correlation (0.20, P = 0.052). In terms of total DDT, intakes of meat, fish, vegetable and milk showed a positive relationship, although none of them provided statistically significant results. No other statistically significant relation between any organochlorines and any food intakes examined was observed in this study. The present study suggests that organochlorine compounds are transported into the human body via foods in the Japanese population. Their effects on health should thus be investigated and monitored.