Carotenoids are yellow to orange red pigments that are ubiquitous in the nature and its annual pro duction amounts to one hundred million ton. This review discussed physicochemical properties, antiox idative activity, anticancer activity of carotenoids and its production technology. Carotenoids, mainly used as food colourants, are characterized by its strong reactive conjugated double bonds, related to oxidation by heat, light, acid, and metal ions. The provitamin A activity of carotenoids is higher in trans form than in cis form. Antioxidative properties of carotenoids are related to ionone structure and long, conjugated polyene chain number. In particular, carotene, astaxanthin, canthaxanthin, and lycopene possess strong antioxidant activity, compared with tocopherol. Especially, carotene, astaxanthin, carotene, fucoxanthin, halocynthiaxanthin and peridinin impart strong anticancer activity against lung cancer, breast cancer, buccal pouch cancer and nerve cell cancer. Carotene and astaxanthin are produced by biotechnology using algae such as Dunaliella salina and Haematococcus pluvalis. But the change of cultivation conditions and screening of algae, efficiently producing carotenoids, are needed for its commercial production. Carotenoids are expected to be used in the various fields through explanation of its biological activity and establishment of commercial production technology.