This study was designed to determine whether lasting attentional deficits result from repeated mild closed head injuries related to participation in youth boxing. Subjects consisted of 10 amateur boxers and 10 basketball players who were participating in tournaments at a youth club. Subjects were matched for age, grade point average, and socioeconomic status. Attentional disruptions were measured by four variables of the Test of Variable Attention (TOVA): Omission errors, a measure of attention; commission errors, a measure of response inhibition and impulsivity; response time, a measure of information processing and motor response speed; and variability of response time, a measure of consistency of attention. The boxers were tested 1 hour after the completion of the boxing tournament and again 8 weeks later. The basketball players were tested once while their tournament was in progress. The results of the study indicate that the cumulative effects of head blows sustained during the boxing season did not have a significant effect on TOVA measures of inattention, inhibition/impulsivity, or information processing and motor response speed. Variability was the only index for which the mean score of the boxers differed significantly from the norm. Consistency of attention was inconsistent and varied at the end of the boxing season and appears to be the only variable affected by the purported head blows. The hypothesis that there would be significant differences between boxers' mean TOVA scores obtained 1 hour after the last match of the tournament and those obtained 8 weeks later was partially supported. The mean scores of the boxers for commission errors and consistency of attention improved significantly between the two testing conditions although their reaction-time score decreased. The hypothesis that the mean TOVA scores of the boxers obtained 1 hour after the last match of their tournament would differ from those of basketball players was supported. The basketball players' reaction time was significantly faster than that of the boxers at the end of the season as well as 8 weeks later.