Ascorbic acid uptake was investigated in isolated, plated human neutrophils using high-performance liquid chromatography with coulometric electrochemical detection. Freshly isolated neutrophils contained 1.3 mM ascorbic acid and accumulated significantly greater amounts when physiologic concentrations of the vitamin were present in the extracellular buffer. In several different buffers uptake was dependent on the presence of calcium and magnesium. Under these conditions, scintillation spectrometry of [14C]ascorbic acid in conjunction with high-performance liquid chromatography was suited for measuring ascorbic acid transport.