A precise, sensitive and high throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of sertraline (SER) and its primary metabolite, N-desmethyl sertraline (NDS) in human plasma is developed and validated. The analytes and the internal standard-fluoxetine were extracted from 300 microL aliquots of human plasma via liquid-liquid extraction in methyl tert-butyl ether. Chromatographic separation was achieved in a run time of 2.5 min on a Betasil C8 column (100 mm x 2 .1 mm, 5 microm) under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for SER, NDS and IS were m/z 306.2-->159.0, 292.1-->159.0 and 310.6-->148.4, respectively. The method was fully validated for its sensitivity, selectivity, linearity, accuracy and precision, matrix effect, stability study and dilution integrity. A linear dynamic range of 0.5-150 ng/mL was established for both the analytes with mean correlation coefficient (r) of 0.9993 and 0.9980, respectively. The intra-batch and inter-batch precision (%CV) across five quality control levels was <or=10.4% for both the analytes. The method was successfully applied to a bioequivalence study of 100mg sertraline tablet formulation in 32 healthy Indian male subjects under fasting condition.