We measured plasma concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in fishermen from the Finnish Baltic Sea area and fishermen fishing in inland lakes. The concentrations clearly correlated with the frequency of fish meals and consumption of Baltic fatty fish. The body burden of PCDD/Fs reached the median level of 170 pg/g toxic equivalents (I-TEq) in fat for Baltic Sea fishermen, with the maximum being 420 pg/g. Results for 2,3,7,8-tetrachlorodibenzo-p-dioxin (range = 4.9-110 pg/g fat) showed that lifetime exposure in a population consuming much Baltic fatty fish can reach the levels of exposures seen in Seveso, Italy, in 1976. After we summed the PCB-TEqs, the total median exposure of Baltic Sea fishermen increased to 290 pg/g TEq in fat, and the highest concentration was 880 pg/g. There was a noted individual variation in fishermen's PCDD/F congener patterns, and it was possible to associate this variation with congener patterns of PCDD/Fs in the fish species that the fisherman reported they had consumed. Linear regression models for ln WHO(PCDD/F)-TEq, ln WHO(PCB)-TEq, and ln total WHO-TEq, from the World Health Organization, explained 48%, 60%, and 53% of the variability, respectively. Age was the only significant predictor of ln WHO(PCDD/F)-TEq, whereas age, amount of fish eaten, and place of residence were significant predictors of ln WHO(PCB)-TEq, and ln total WHO-TEq.