Abstract: Fatigue is a functional state characterized by a persistent decrease in performance. A system for recording the degree of driver fatigue based on the tremor modulation signal model is proposed. The amplitude and frequency of natural tremor oscillations of the eye are taken as an indicator of the degree of fatigue. It has been experimentally proven that tremor is an adequate marker of the condition of fatigue. The objectivity and effectiveness of the proposed method were evaluated in comparison with classical methods for assessing the functional state of the central nervous system—the simple visual-motor reaction and visual-motor coordination times. It was found that the probability of correct prediction of the condition of fatigue by measuring the parameters of natural tremor oscillations of the eye (amplitude and frequency) with the data of simple visual-motor response and visual-motor coordination task is 87.4 and 88.6%, respectively.