The purpose of this study was to compare and analyze test scores on the Woodcock-Johnson Psycho-Educational Battery (Battery) and the Wechsler Intelligence Scale for Children -- Revised (WISC-R) for a sample of subjects classified as learning disabled and a sample of subjects classified as gifted and talented. Subjects were randomly selected and included 51 school-identified learning disabled students and 46 school-identified gifted and talented students. All subjects were administered the Woodcock-Johnson Tests of Cognitive Ability (WJTCA), the Woodcock-Johnson Tests of Achievement (WJTA) and the WISC-R. The specific areas of investigation for each sample included: (a) performance on the Achievement-Aptitude Profile of the Battery, (b) comparability of full scale scores, (c) performance on the Cognitive clusters of the Battery, (d) performance on the Achievement clusters of the Battery, and (e) the magnitude of Verbal-Performance Scale Score discrepancies on the WISC-R. Results indicated that the majority (74.5%) of the subjects classified as learning disabled and a few (10.9%) of the subjects classified as gifted and talented evidenced a moderate or severe deficit on the Achievement-Aptitude Profile. The subjects classified as learning disabled scored significantly higher on the Full Scale score of the WISC-R than on the full scale score of the WJTCA, while the difference between full scale scores was not significant for the subject classified as gifted and talented. An important finding was that scores obtained on the Reasoning cluster were invalid for subjects in both samples. Further analyses indicated that the alternative clusters, Oral Language and Broad Reasoning (Woodcock, 1983) provided a more accurate appraisal of abilities for each sample. Overall, the study provided insights regarding test performance on the Battery and the WISC-R for these two diverse samples.