The aim of the paper is to present a novel tracking system for the assessment and training of grip force control. The system consists of two force measuring units of different shapes, which can be connected to a personal computer for visual feedback and data acquisition. We present the results of the assessment of the grip force control in 32 healthy subjects of different age groups and preliminary results obtained in a patient after head-injury who was treated with Botulinum-Toxin for hand spasticity. The proposed tracking system was also applied as a training tool in 10 post-stroke patients to possibly improve their grip force control. The results in healthy subjects showed significant differences in grip force control among different age groups. In the patient after Botulinum-Toxin treatment the method revealed noticeable effects of the therapy on the patient's tracking performance. Training with the tracking system showed considerable improvements in the grip force control in 8 out of 10 stroke patients. The proposed tracking method is aimed to be used in connection with different rehabilitation therapies (e.g. physiotherapy, functional electrical stimulation, drug treatment) to follow the influence of the therapy on patient's muscular strength and grip force control.