Abstract. Quantitative evaluation parameters for care-giving motions were investigated by analyzing three-dimensional motion data of skilled and unskilled caregivers. Subjects were three skilled caregivers, each of whom had over 12 yrs of clinical experience, and four physical therapy students. We recorded a typical care-giving motion between a caregiver and a care-receiver three times for each caregiver/receiver pair with a 3-D motion analysis system (VICON system, Oxford Metrics, UK). We did time-series analyses to extract performance evaluation parameters from observed indexes such as trajectories, velocities, accelerations of the body's center of gravity (COG), jerk-cost, and impulse. The analyzed motion was lifting a patient lying on a bed into the sitting position. The skilled caregivers' operation times were shorter than those of the unskilled caregivers. The COG trajectories of skilled caregivers showed smoother and better reproducibility over the three trials, and the COG velocity curves showed a high single peak at start up. The jerk-cost and impulse of skilled caregivers were lower than those of unskilled caregivers. We found reproducibility and smoothness of movement to be good evaluation parameters for care-giving motions. The measurement indexes observed in this study should be introduced to improve evaluation of the education of unskilled caregivers.