The Kinect sensor (TM), originally developed for gaming purposes, may have interesting possibilities for other fields such as posture and motion assessment. The ability of the Kinect sensor (TM) to perform biomechanical measurements has previously been studied and shows promising results. However inter-day repeatability of the device is still not known. This study assessed the intra and inter-day repeatability of the Kinect sensor (TM) compared to a standard stereophotogrammetric device during posture assessment for measuring segment lengths. Forty subjects took part in the study. Five motionless captures were performed in one session to assess posture. Data were simultaneously recorded with both devices. Similar ICC values were found for intra-day repeatability (ICC=0.94 for the Kinect device and 0.98 for the stereophotogrammetric device) and inter-day repeatability (ICC=0.88 and 0.87 respectively). Results of this study suggest that a cost-effective, easy to use and portable single markerless camera offers the same repeatability during posture assessment as an expensive, time-consuming and non-transportable marker-based device.