A new reverse phase high performance liquid chromatography (RP-HPLC) method for the quantitative determination of Sitagliptin in human plasma was developed and validated as per US-FDA guidelines. The drug was spiked in the plasma and extracted with mobile phase by precipitation method. The extracted analyte was injected into an INTERSIL C18 column (150 mm × 4.6 mm, 5μm), maintained at ambient temperature and effluent was monitored at 267 nm. The mobile phase consisting of acetonitrile: methanol: buffer (2:3:5 v/v). The pH of the mobile phase was adjusted to 4.0 by using O-phosphoric acid. The flow rate was maintained at 1.0 mL/min. The developed method shows high specificity for sitagliptin. Calibration curve was plotted with a range from 25-125µg/mL (r2>0.9994). The lower limit of quantification (LLOQ) was found to be 25μg/mL. The method was validated for parameters like accuracy, precision, recovery, linearity, range, stability and sensitivity. This RP-HPLC method is suitable for determining the concentration of sitagliptin in human plasma and it was applied to routine analysis for determination of the Sitagliptin from dosage form during pharmacokinetic study.