The general exposure of humans to polychlorinated biphenyls (PCBs) and ΣDDT (i.e., p,p′-DDT + p,p′-DDE + p,p′-DDD) in Wales (UK) was determined through the analysis of adipose tissue samples collected from 75 individuals during post-mortem examinations in 1990–1991. Fifty PCB congeners were screened, of which 29 were identified in most of the samples. Congener IUPAC numbers 138, 153 and 180 were the most abundant compounds, accounting for an average of 55% of the ΣPCB congeners analysed. ΣPCB concentrations varied between 0·2 and 1·8 μg g−1 of adipose tissue and were positively correlated with the donors age and negatively associated with the percentage of lipid in the adipose tissue. A progressive change in the congener pattern was noted with increasing subject age. Tissue from older individuals generally contained a relatively high proportion of the more persistent and higher chlorinated congeners. ΣDDT concentrations ranged from 0·11 to 5·6 μg g−1 adipose tissue, with p,p′-DDE contributing 96% towards the ΣDDT concentration. ΣDDT levels were also positively correlated with age. No significant differences in the ΣPCB and ΣDDT concentrations were noted between males and females, between people living in rural and urban locations or with the subjects' body weight at the time of their death.