A growing body of opinion, research, and legislation [PL 98-524] implies that school psychological evaluations with adolescents and young adults should routinely include estimates of vocational interests and aptitude. Certainly all secondary level special education evaluations should include this important vocational component. Evidence suggests that the experience of career development among learning disabled young adults is particularly frustrating and difficult without early planning and exploration of options. This study examines the utility of traditionally available psychometric data in assisting the clinician make initial, exploratory estimates of vocational aptitude without referring the client for specialized testing. Wechsler Adult Intelligence Scale - Revised [WAIS-R], and General Aptitude Test Battery [GATB] scores were subjected to a multivariate, canonical correlation analysis to examine the overlap among constructs estimated by these sets of variables. The sample was composed of 148 learning disabled young adults enrolled in a state supported vocational rehabilitation program. Three significant canonical correlations were interpreted. The redundancy index showed that 34% of the variance in GATB aptitudes is explained by three linear combinations of WAIS-R subtest scaled scores, and that 31% of the WAIS-R subtest variance is predictable from three composites of GATB aptitude scores. Analysis of the structure correlations suggests that the first pair of canonical variates [Rc = .87] share a general intelligence, or verbal comprehension factor. A second pair [Rc= .73] share a perceptual and motor coordination construct. The third pair of canonical variates [Rc = .61] define a perceptual speed, or psychomotor construct that overlaps both the GATB and the WAIS-R set of test scores. There is evidence that GATB and WAIS-R estimate similar, but essentially independent dimensions of the same three psychoeducational constructs. WAIS-R may provide better estimates of fluid ability than GATB; and GATB may provide better estimates of crystallized ability than WAIS-R. Clinical implications for psychologists making exploratory estimates of vocational ability and aptitude from clinical profiles of WAIS-R scaled scores are discussed. Assessment issues with respect to the learning disabled young adult are also presented. [175 references] / Ed. D.