【Objective】The purpose of this study was to investigate the foot kinematics as related to the Navicular Drop test and to examine the validity of the Navicular Drop test. 【Methods】Twelve healthy subjects participated in this study. The difference between the original height of the navicular when in a neutral subtalar joint position and the height of the navicular when in a relaxed stance position (ND) was measured using a 3D motion analysis system. At the same time, the changes in the angles between each foot segment in these positions were measured. The correlations between the ND and the change in the angle between each foot segment were determined with the Pearson product moment correlation coefficient. 【Result】There were significant correlations between the ND and the change in the rearfoot pronation angle relative to the forefoot (r=0.63). 【Conclusion】The results of this study supported the validity of the Navicular Drop test as a method to measure rearfoot pronation.