A study was conducted to (1) determine the concentration of DDT/DDE in the breast milk of mothers residing in the Yakima river basin (WA, USA), (2) assess the relative impact of fish consumption on the total DDT/DDE body burden, and (3) determine if the amount of DDT/DDE received by their breastfed infants exceeds levels that could produce deleterious effects. Results indicate that fish consumption did not significantly increase DDT/DDE breast milk concentrations. Subjects born in Mexico had elevated levels of DDT/DDE in breast milk compared to levels found in US born subjects regardless of fish consumption. Infant daily intake levels for the various subject groups were determined and compared to acceptable and tolerable daily intake levels. With benefits of breast milk well understood, breastfeeding should still be strongly recommended for these mothers.