Concentrations of neutral organochlorine compounds (OCs) in blood compartments and adipose tissue were determined in three groups of subjects. In 12 healthy volunteers a positive correlation was found between DDT residue levels in paired serum/adipose tissue samples when the concentrations were calculated on a fat-weight basis (r = 0.74, p less than 0.05); positive correlations were also found for PCB and HCB when the calculations were based on a wet-weight basis (r = 0.68, p less than 0.01; r = 0.69, p less than 0.01). For lindane the correlation coefficient for paired serum/adipose tissue samples was -0.94 (p less than 0.01). The association between adipose tissue and blood cells was weaker than that obtained for serum. These readily obtainable samples are adequate for estimating, or monitoring, the total burden of neutral organochlorines in adipose tissue, especially in cases of low chronic exposure, such as those found in epidemiological studies. In paired liver-adipose tissue samples from 23 autopsy cases, no correlation was found either on a wet- or fat-weight basis. In 131 adults resident in southern and eastern Finland the concentration medians for serum were 1.8, 2.0 and 0.3 ng g-1 wet wt for DDT compounds. PCB and HCB, respectively. This study indicates that monitoring of fat/serum ratios may provide, with tissue concentrations, more information about human exposure to OCs.