This study was conducted to determine the effect of astaxanthin (AX) produced by Phaffia rhodozyma (PR) on growth performance, antioxidant activities, relative organ weight, and meat quality in Pekin ducks. A total of 1,440 female one-day-old Pekin ducklings (52.3 +/- 0.4 g) were blocked based on body weight (BW), and randomly allotted to 3 treatments with 8 replicates of 60 birds each. The experiment lasted for 6 wk, and dietary treatments included corn-soybean meal-based diet supplemented with 0, 0.15, and 0.3% PR. The supplementation of AX increased (P < 0.05) body weight gain (BWG) linearly and reduced (P < 0.05) feed-to-gain ratio (F/G) linearly during days 22 to 42. BWG and final BW was increased (P < 0.05) linearly by AX supplementation throughout the experiment. The inclusion of AX increased (P < 0.05) superoxide dismutase, glutathione peroxidase, total antioxidative capacity, and interleukin-6 in the serum linearly, as well as decreased (P < 0.05) serum malondialdehyde linearly. The relative weight of abdominal fat was increased (P < 0.05) linearly by AX supplementation. The inclusion of AX decreased (P < 0.05) cook loss linearly, but increased (P < 0.05) pH(24h), water holding capacity and redness (a*) linearly. Taken together, the supplementation of AX (3.458 or 6.915 mg/kg diet) from PR improved final BW, BWG during days 22 to 42 and 1 to 42 and reduced F/G during days 22 to 42, as well as caused positive effects on antioxidant function and meat quality.