Two studies were conducted in which the Wechsler Intelligence Scale for Children--Revised (WISC-R) and the Wechsler Adult Intelligence Scale--Revised (WAIS-R) were administered in a counterbalanced design to 144 (72 in each study) randomly selected high school students between the ages of 16 years, 0 months and 16 years, 11 months in order to determine their equivalence by testing the equality of (a) means; (b) variances; and (c) validity coefficients based on the scaled scores and IQs. Results indicated that the two scales, with the possible exception of the Verbal IQ, were not equivalent (either with respect to subtest scores or IQs) because they did not satisfy the necessary criteria. These findings contradict those reported by Wechsler in 1981 concerning these two scales for a similar age group.