Little is known about the consequences of repetitive sub-concussive injuries (very mild traumatic brain injuries – vMTBI), in schoolboy rugby players. PURPOSE The aim of this study was to compare the end of season neuropsychological, electroencephalographic (EEG) status, and academic performance of players in a secondary school rugby team who, during the course of the season sustained only repetitive vMTBI to those players who sustained mild traumatic brain injuries (MTBI) and a sedentary control group. METHODS A cohort of 20 secondary school male rugby players was followed for a season. A sports physician documented all vMTBI and MTBI injuries. At the end of the season, the players were divided into a vMTBI group [N=11, 17.9 (0.54) yrs], and a MTBI group [N=9, 17.5 (0.88) years] according to the injuries sustained during the season. At the end of the season an EEG-test was done on each subject according to the international 10–20 system. Fast Fourier transformation of each EEG was used to obtain power spectrum areas in the Δ(0-3Hz), τ(4-7Hz), α(8–13Hz) and β(14–25,30 Hz) frequencies. The mean amplitude for each of the 21 EEG positions and for the different wave types were calculated for each group and compared. End of season Neuropsychological tests (Colour Trial Test 1 and 2, Digit Symbol Substitution Test, Wechsler Memory Scale-Revised (WMS-R) Test for verbal-, visual-, general-, delayed and attention/concentration) were conducted on the 2 groups and on a control group [CON=9, 17.3 (0.5) years] matched for age- and educational level and who did not participate in any collision sport. The academic results of different subjects (Languages, Science, Mathematics and Latin) were obtained from the school and compared for the year that the study was done and for the two years preceding the study. RESULTS EEG test results showed that the mean amplitudes of the total, the β- and τ-waves' frequencies in the right temporal regions tested, were significant smaller (p<0.05) for the MTBI and the vMTBI groups when compared with the CON group. There were no significant differences between the groups for the neuropsychological tests and academic results. CONCLUSIONS Subtle EEG changes at the end of the rugby season are present in school rugby players who sustained vMTBI and MTBI during a single rugby season.