Introduction. A significant increase in the study load, the expansion of the program material, the introduction of new academic subjects, the use of new, including copyright, pedagogical technologies (computer training, modular lessons, etc.) in educational institutions of an innovative type creates the preconditions for the development of functional tension of the central nervous system, the rapid onset of fatigue and a decrease in the mental performance of students. The aim of the study is to scientifically substantiate a non-invasive, non-drug way of increasing mental performance in adolescents of senior school age. Materials and methods. The method consisted in the implementation of four stages: at the first stage, 100 students of the multidisciplinary lyceum underwent a preliminary computer assessment of the level of mental performance by the method of variational chronoreflexometry; at the second stage, the students were taught the skills of functional biocontrol using diaphragmatic relaxation breathing on the hardware-software complex “Mikart-M”; at the third stage, each student, depending on the degree of mastering the methodology, was given recommendations on the mode and frequency of training. Two groups were formed from the students, where the first group was represented by the surveyed who independently and regularly performed pieces of training for two weeks (n = 48), the second group consisted of adolescents who did not perform pieces of training (n = 52). At the fourth stage, the effectiveness of the developed method was assessed by comparative analysis of data before and after training in functional biocontrol in students of both groups. Results. It was found that among the students of the 1st group who regularly performed breathing for two weeks, the number of subjects with optimal working capacity doubled, and the proportion of students with significantly reduced mental performance decreased 16.7 times, which indicated the high efficiency of the developed method increasing mental performance; in turn, among the adolescents of the 2nd group who did pieces of training irregularly, an opposite tendency was revealed for a 15.5-fold decrease in the number of subjects with typical mental performance. Limitations. The results obtained require verification on other samples with the expansion of the age of students and the type of educational institution; supplementing data on the level of mental performance of lyceum students with the results of academic performance, which also characterizes the level of mental performance; lengthening the observation period for fixed indicators after conducting pieces of training to clarify the timing of maintaining changes in indicators that affect and characterize the performance. Conclusion. Thus, the developed method is an effective tool for increasing mental performance in senior school adolescents, making it possible to recommend it for implementation and mass use among medical workers and teachers of educational institutions.