Two-month-old female mink were fed diets based on either Baltic herring (Clupea harengus membras) or freshwater smelt (Osmerus eperlanus) for 21 weeks. A portion of the smelt-fed mink were exposed orally to polychlorinated biphenyls (PCBs), Aroclor 1242 (1 mg/d). Retinol (vitamin A1), 3,4-didehydroretinol (vitamin A2), and their different fatty acyl esters were studied in hepatic tissue, microsomes, and cytosol by argentated reversed-phase high-performance liquid chromatography. As a result of Aroclor exposure, concentrations of the fatty acyl esters of vitamins A1 and A2 were about one-tenth and those of unesterified A2 one-fourth those of the control levels. In the fatty acyl esters, percentages of stearates (A1-18:0 and A2-18:0) increased at the expense of the other fatty acyl esters. The Aroclor exposure decreased concentrations of alcoholic and esterified forms of the A2 analog more than those of the corresponding A1 analog. In microsomes, Aroclor decreased the alcoholic and esterified vitamin analogs to the same extent (to 9–17%). In the cytosol compared to the control, the concentrations of the vitamin esters fell below 10%, but the alcoholic analogs remained at 30 to 40%. Despite equal dietary supply, in mink fed on Baltic herring, the hepatic levels of vitamin A1 were only about one-third of the values found in the smelt-fed mink. The organochlorines also altered hepatic lipid composition and impaired breeding and kit growth. In the kits of the females fed on Baltic herring, blood hemoglobin was decreased.