ABSTRACT. The influence of the season on serum vitamin A, E and β-carotene concentrations was studied in Japanese Black breeding cattle. Blood samples were collected from 13 cows once a month for a year to determine the serum vitamin concentrations. Mean serum concentrations (± SE) of retinol, α-tocopherol and β-carotene were 21.3 ± 0.5 µg/dl (range 9.9 to 44.9), 215.9 ± 8.0 µg/dl (range 59.7 to 551.6) and 67.3 ± 5.1 µg/dl (range 10.6 to 425.2), respectively. All these concentrations were lower than the recommended levels. Serum retinol and α-tocopherol concentrations in summer were lower than those in winter. These results suggest that the vitamin A, E and β-carotene status of Japanese Black breeding cows is inadequate, and feeding high quality forages or dietary vitamin supplementat ion during summer should be recommended. KEY WORDS: bovine, fat soluble vitamin, seasonal change.