Objectives: This study was conducted in order to develop and obtain the nonnative data of the computerized Comprehensive Attention Test(CAT) in Korean children and adolescents. It also aimed to evaluate the reliability and validity of the CAT. Methods: We developed the computerized CAT which includes the selective attention task, the sustained attention to response task, the flanker task, the divided attention task, and the spatial working memory task. We investigated the test-retest reliability and the construction validity of this computerized version by using the data from 21 children, and gathered the nonnative data of 9l2 subjects, aged 4 to 15 years, dwelling in the Metropolitan Seoul area in 2008. Results: No statistical differences between means of the tests and retests of the CAT were observed. The mean of the correlation coefficient of the test-retest scores was 0.715. The results from the factor analyses explained 51.7% of the cumulative variance. In addition, the nonnative data for all of the CAT subtests were obtained. Conclusion: The computerized CAT can be used as a reliable and valid tool in both clinical and research settings for Korean children and adolescents with or without neuropsychiatric conditions such as attention deficit.