Biofortification efforts have increased concentrations of bioactive compounds in carrots. We measured the antioxidant potential and vitamin A bioefficacy of 4 biofortified carrot varieties [purple/orange, purple/orange/red, orange/red, and orange] in Mongolian gerbils (n = 73). Following a 4-wk vitamin A depletion period and baseline kill (n = 7), freeze-dried carrot powders were mixed into purified feeds and fed to 6 groups (n = 11/group) for 4 wk. White carrot-fed control and vitamin A-supplemented groups were used to calculate carrot provitamin A bioefficacy. Antioxidant capacities of carrot powders, sera, and livers were determined using the 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assay and carotenoid and retinol concentrations were determined by HPLC. Antioxidant capacity of liver extracts from the 4 colored carrot-fed groups [10.1 +/- 1.2 mumol Trolox equivalent antioxidant capacity (TEAC)/g] was significantly higher than the white carrot-fed control group (9.3 +/- 0.9 mumol TEAC/g) and vitamin A-supplemented group (8.8 +/- 1.4 mumol TEAC/g) (P < 0.05). Liver retinol stores in the colored carrot-fed groups (0.62 +/- 0.13 to 0.67 +/- 0.08 mumol retinol/liver) did not differ and were higher than the white carrot-fed control group (0.32 +/- 0.08 mumol retinol/g) (P < 0.0001). Serum antioxidant capacity and retinol did not differ among treatment groups. Liver antioxidant capacity and vitamin A stores were higher in gerbils fed colored carrots than in those fed white carrots. Antioxidant activity is one of several proposed mechanisms by which plant foods, like biofortified carrots, may provide additional health benefits beyond maintenance of vitamin A status.