It is found that the interaction of retinol, ergocalciferol, and cholecalciferol with electrochemically generated bromine proceeds rapidly and quantitatively. The stoichiometric coefficients of the reaction are 1:2, 1:7, and 1:3, respectively. A coulometric determination of microgram amounts of individual liposoluble antioxidants in model solutions was performed with RSD = 1–5%. The voltammetric response of retinol and α-tocopherol was studied at a stationary platinum microelectrode in 0.1 M HClO4 and 0.1 M CH3COONa in acetonitrile. The quantification limit for α-tocopherol is 2.7 × 10−4 M in 0.1 M HClO4, and the quantification limits for retinol are 4.1 × 10−5 M in 0.1 M HClO4 and 2.1 × 10−5 M in 0.1 M CH3COONa. A procedure for the coulometric determination of total free liposoluble antioxidants in human blood serum is proposed.