The commonly used methods to test the authenticities of medicinal plants may either require a long and complicated task or would demand for high cost operation. In this study, six AT-cut quartz crystal microbalance (QCM) sensors, leading to the development of electronic nose, was employed as an alternative low cost and reliablemethod of differentiating commonly used mint plants - yerba buena (Mentha cordifolia opiz.), peppermint (Mentha piperita L.), and spearmint (Mentha spicata L.). The QCM sensors, with gold electrodes on both sides were coated with different sensing materials. Each plant sample was exposed to sensor chamber, with one sensor at a time. The headspace vapors from the incubated sample were carried tothe sensor chamber by a stream of nitrogen gas, and the vapors were reversibly adsorbed when in contact with the sensing layer of QCM. The sensor gave a steady response to the headspace vapors, and exhibited good reversibility and reproducibility at an acceptable response time. The integrated response of all the sensors, using polar plot, created an odor graphical profile of each plant. A good discrimination of the plant samples was achieved by Principal Component Analysis(PCA) using the commercial Six Sigma Minitab15 software program.