In basketball, reaction speed is important: how quickly a player reacts to an external stimulus, finds the right solution and implements it on the playground, often determines the outcome of the match. The aim of the study is to analyze the peculiarities of the course of mental processes and to identify their relationship with the technical readiness of basketball players at the training stage of preparation. To assess mental processes, we used: a proofreading test, a test with a school ruler, an individual minute, and a tapping test. Standards were used to check technical readiness: the number of hits from 10 free throws, the time of the throw-in motion, and the total number of hits in the ring, shuttle running with ball driving (5x10). The study involved girls aged 15-16 years who had been playing basketball for at least 5 years and had sports grades. The basketball players were examined in September 2021 and May 2022. In this study we found statistical differences between the initial and final levels in terms of the number of errors in the proofreading test (27.91%, p<0.05), the reaction rate to a moving object (27.57%, p<0.05), the duration of the individual minute (13.59%, p<0.05), the result of the tapping test with the right and left hands (the differences were 21.82%, 15.46%, respectively, p<0.05), as well as the coefficient of functional asymmetry (35.67%, p<0.05). The data obtained require a deeper study of ways to increase the effectiveness of training activities that allow influencing traditional training.