A sensitive and selective gas chromatography-mass spectrometry (GC-MS) method was developed and fully validated for the determination of vildagliptin (VIL) in pharmaceutical formulation. Prior to GC-MS analysis, VIL was efficiently derivatized with MSTFA/NH4I/beta-mercaptoethanol at 60 degrees C for 30 min. The obtained O-TMS derivative of VIL was detected by selected ion monitoring mode using the diagnostic ions m/z 223 and 252. Nandrolone was chosen as internal standard. The GC-MS method was fully validated by the following validation parameters: limit of detection (LOD) and quantitation (LOQ), linearity, precision, accuracy, specificity, stability, robustness, and ruggedness. LOD and LOQ were found to be 1.5 and 3.5 ng mL(-1), respectively. The GC-MS method is linear in the range of 3.5-300 ng mL(-1). The intra-and interday precision values were less than <= 3.62%. The intra-and interday accuracy values were found in the range of -0.26-2.06%. Finally, the GC-MS method was successfully applied to determine VIL in pharmaceutical formulation.