Technical Abstract: Fruit from forty-two blueberry (Vaccinium species) cultivars, including thirty-six rabbiteye rabbiteye cultivars (Vaccinium ashei Reade), three V. ashei hybrid derivatives and three northern highbush (V. corymbosum L.) standards were evaluated for antioxidant activities (AA), levels of antioxidant enzymes [catalase (CAT), ascorbate peroxidase (AsA-POD), glutathione reductase (GR), glutathione peroxidase (GSH-POD), superoxide dismutase (SOD), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDAR), and guaiacol peroxidase (G-POD)], and anthioxidant nonenzyme components [ascorbic acid (ASA) and glutathione (GSH)]. The results of this study showed that cultivars had varying levels of AA, a wide range of antioxidant enzyme activities, and various amounts of nonenzyme components. The correlations between AA and all of the enzyme activities or nonenzyme components were positive and high in the forty-two cultivars tested in this study. The correlation (R2) values between AA and CAT, SOD, DHAR, MDAR, GSH-POD, GR, G-POD, and AsA-POD were 0.91, 0.91, 0.91, 0.91, 0.90, 0.90, 0.90, and 0.90, respectively. The correlations between AA and ASA and GSH were 0.94 and 0.92, respectively. Among all 42 cultivars, ‘Early May’ had the highest activities of the AA, AsA-POD, G-POD, DHAR, and MDAR; and the highest amounts of ASA and GSH; whereas ‘Elliott’ had highest levels of GR, GSH and SOD. The cultivars with high antioxidants and antioxidant enzyme activities may be especially useful in a breeding program for developing more nutritious blueberry varieties with improved health-promoting quality for consumers.