In South Carolina, U.S.A., mink have been reintroduced from two apparently healthy populations to areas where populations have existed in the past but have been extirpated. High mortality was observed during transport of mink from the source populations. In order to elucidate the potential effects of dioxin-like compounds on the survival and reproduction of mink, concentrations of total polychlorinated biphenyls (PCBs), p,p'-DDE, dioxin-like PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) were measured in livers of mink collected from the source populations in South Carolina and Louisiana. Concentrations of total 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) for the South Carolina and Louisiana mink were 21 and 14 pg g(-1), wet wt., respectively. PCB and TEQ concentrations were close to the threshold values that can, under laboratory conditions, elicit toxic effects in ranch mink. Therefore, any additional exposures of these populations to TEQs might adversely affect their populations.