A rapid, easy, and accurate method for the determination of uric acid and ascorbic acid in human serum by reversed-phase high-performance liquid chromatography with electrochemical detection has been developed. Human serum (0.5 ml) was mixed with 1.5 ml of an aqueous solution containing 2.0% metaphosphoric acid and the mixture was centrifuged at 3000g for 30 min. The supernatant was passed through a membrane filter to remove the particulate matter. Ten microliters of the filtrate was injected into the chromatographic system employed in this study. Complete separation of uric acid and ascorbic acid was achieved in about 2 min. The assay limit for quantitation was about 10 pg for uric acid and ascorbic acid under the present chromatographic conditions. The analytical recoveries of uric acid and ascorbic acid in human serum samples were found to be almost 100%.