Abstract: A liquid chromatographytandem mass spectrometry (LC-MS/MS) method was developed to determine clarithromycin in human plasma. The linearity was obtained in the range of 10~5 000 ng/mL in plasma and the limit of quantification was 10 ng/mL. The intra and inter-day precision (RSD) were less than 2.9% and 9.2%, respectively. Accuracy(relative error)was with in 3.2%. The method was proved to be convenient, rapid and accurate enough to be applied to the pharmacokinetic studies of clarithromycin in human plasma.