A rapid and sensitive liquid chromatography tandem mass spectrometry(LC-MS/MS) method has been developed and validated for the determination of moxifloxacin(MOXI) in human plasma. After a simple protein precipitation using acetonitrile, the post treatment samples were analysed on a C18 column interfaced with a Triple Quadropole Tandem Mass Spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of 0.1% formic acid–acetonitrile(60:40, v/v). Ciprofloxacin(CIPRO) was used as an internal standard. The analyte and internal standard(CIPRO) were monitored in the multiple reaction monitoring mode(MRM). The mass transition ion-pair has been followed as m/z 402→358.2 for MOXI and 332→288.1 for CIPRO. The method was linear in the concentration range of 25–5000 ng/mL. The lower limit of quantification was 25 ng/mL. The intra- and inter-day precision(relative standard deviation) and accuracy(relative error) values were within 12.4%. Each plasma sample was analyzed within 3 min. A rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS / MS) method has been developed and validated for the determination of moxifloxacin (MOXI) in human plasma. After a simple protein precipitation using acetonitrile, the post treatment samples were analyzed on a C18 column interfaced with a Triple Quadropole Tandem Mass Spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of 0.1% formic acid-acetonitrile (60:40, v / v). Ciprofloxacin (CIPRO) was used as an internal standard. The analyte and internal standard (CIPRO) were monitored in the multiple reaction monitoring mode (MRM). The mass transition ion-pair has been followed as m / z 402 → 358.2 for MOXI and 332 → 288.1 for CIPRO. The method The lower limit of quantification was 25 ng / mL. The intra- and inter-day precision (relative standard deviation) and accuracy (relative error) values ​​were within 12.4%. E ach plasma sample was analyzed within 3 min.