The goal of this study is to evaluate the effects of upper limb robot-assisted treatment in a group of 25 subacute post-stroke patients using clinical outcome measures and kinematic parameters. Fugl-Meyer (FM) Assessment scale and Motricity Index (MI) were used for clinical assessment, and a set of kinematic parameters was computed. A significant decrease in motor impairment after the robot-assisted treatment (FM p<0.05 and MI p<0.05) was found. Significant improvements of upper limb motor performance was found after 2 weeks (p<0.001); subsequently, no further significant improvements were observed. Our results confirm that robotic treatment is effective to reduce upper limb motor impairment in subacute stroke patients. Kinematic parameters can provide important information on mechanisms underlying motor recovery and the frequent assessment of their values can contribute to identify an appropriate number of robotic therapy sessions as to reach soon substantial improvements.