Marker less motion capture systems such as the Kinect are increasingly used in clinical rehabilitation. Here, we aim to identify which measures are reliably assessed with the Kinect during seated hand reaching. Participants performed seated reaching tasks in both spontaneous and maximal (by minimizing trunk movement) way with. 3-dimensional hand movement and joint motions of the upper extremity and trunk were simultaneously recorded with the Kinect (Microsoft, USA) and with the VICON (Oxford Metrics, UK), the latter being the reference system. For each kinematic outcome, the validity of the Kinect was assessed with ICC, linear regression and Bland & Altmann plots. Instantaneous Cartesian and angular measures with the Kinect are not precise enough to reliably assess Cartesian and angular kinematics over time. Results showed that Kinect could accurately and reliably assess postural and angular measurement during seated reaching. It consolidates the idea that well designed Kinect-based protocols could be a wonderful way to easily assess specific information, further available for automatized quantitative diagnostics and individualized rehabilitation.