Purpose: to study the indicators of spatial perception of martial artists using the provisions of uncertainty theories. Material and Methods. Research methods: analysis and synthesis of scientific and methodological literature, psychophysiological measurements, mathematical and statistical methods using licensed programs RStudio and Numbers. The study was conducted in several stages. At the first stage, taking into account the peculiarities of martial artists' sports activities, a mobile application «Spatial Perception» was developed to assess their spatial perception. At the second stage, the use of the application in the field was tested and the capabilities of the mobile application were expanded in terms of obtaining detailed characteristics of measurements using the provisions of the theory of uncertainty. The study involved junior taekwondo athletes aged 14-17 years (n=25, qualification: 1st category and candidates for master of sports of Ukraine). Results: according to the measurements of the studied martial artists, it can be noted that the highest frequency of reaction time indicators lies within 583 ms (n=291). At the second stage of the test exercise, where the performer needs to react to non-moving 3D figures, there is an increase in the interquartile range by 22 ms and a violation of the symmetry of the data. It was at this stage that the largest value of the standard deviation was noted (SD=172,0 ms). This indicates a high variability of reaction time (V=22,7 %). Also, we can see an increase in reaction time at the fourth stage compared to the result of the third stage by 11,5 ms and an increase in the percentage of errors by 1,4 % (at this stage, the highest percentage of errors was recorded at 8,2 %). Based on the use of membership functions, fuzzy sets were created, which made it possible to evaluate each indicator on a scale from 0 to 1. The analysis of the test exercise performance by martial artists who have the category of KMS (candidate for master of sports) shows that the overall score for the entire test is «Good», the weighting factor is 0,74, which is closer to the «Excellent» score. It should be noted that the highest weighting coefficient was observed in the second stage of the test task. The high weighting factor (0,79) at this stage reflects the ability to quickly recognize 3D shapes in space based on the analysis of individual parts of the shapes. We can also note the low percentage of errors (3 %) at the fourth, most difficult stage. This may indicate the ability to maintain attention on the object and resistance to disturbing visual stimuli. According to the results of the martial artists who have the 1st category, it was noted that they performed the test exercise with a score of «Good» and have a total weighting factor of 0,34. The score at each stage of the test is «Good», but the values of the weighting coefficients are closer to the «Satisfactory» score. The values of the weighting coefficients demonstrate that the level of spatial perception of this group of athletes is below average. It is also worth noting the increase in the percentage of errors, especially at the fourth stage (11,7 %), which indicates a negative impact on the reaction time of additional visual stimuli. The biggest difference between weight coefficients of the studied groups was noted at the second stage and made 49 %, the smallest at the fourth stage – 27 %. Conclusions. The use of fuzzy logic methods is a promising area of activity and finds its application in sports activities. The levels of manifestation of spatial perception by weight coefficients have been determined. Thus, a group of sportsmen with a category of CMS received an overall mark for the whole test «Good»with a weight coefficient of 0,74, and martial artists of the 1st category received an overall mark for the whole test «Good» with a weight coefficient of 0,34. Comparison of results of the estimation of reaction time of martial artists with a category of CMS with sportsmen of the 1st category testifies that there are statistically significant differences between indicators (p<0,05). The use of the theory of uncertainty in the assessment of spatial perception makes it possible to create flexible assessment systems and allows combining different indicators into one complex result.