OBJECTIVES: The purpose of the study was to evaluate how the visual and auditory TOVA along with the IQ scores can differentiate the attentional deficit, both in children with ADHD only and in children with clinical diagnoses other than ADHD. METHODS: Forty seven children were divided into two groups, who were diagnosed as ADHD only and non-ADHD. One child & adolescent psychiatrist and one clinical psychologist were involved in the diagnostic process. Psychological tests battery including TOVA- visual and auditory was applied to all children. The raw data from the results was analyzed statistically by ANCOVA. RESULTS: ADHD children were significantly scored lower in total IQ scores, as well as in all the subscores of IQ tests except similarities and vocabulary, though all of the children were classified within normal limit in terms of total IQ scores. Among the subscores of the IQ tests, the scores of arithmatic, digit span and coding were more significantly lower in ADHD group. And the ADHD children were significantly more impaired in performance in the variables of commission for the first half & total with visual TOVA, in the variables of commission for the second half & total with auditory TOVA. CONCLUSION: The ADHD children could be differentiated by the variables of both commission and variability of auditory TOVA. Assuming that the subscores of arithmatic, digit span and coding in the IQ test, as well as the variables of commission and variability of auditory TOVA reflect the ability of impulse control, the results suggest that the ADHD children would be more impaired in impulse-control than the children diagnosed other than ADHD.