Two sets of diagnostic measures were administered to a group of 35 adults with well-documented histories of specific language impairment and to a control group of 35 normal language users. These measures involved the comprehension and production of words and sentences in formal and spontaneous speaking activities as well as measures of verbal memory and auditory temporal perceptual ability. One set of tasks was administered in a standard face-to-face setting and the other set was given over the telephone. Multivariate and univariate tests indicated that the adults with a history of specific language impairment performed more poorly on all tasks administered. A discriminant analysis of the two sets of measures indicated that four measures in each set identified language-impaired individuals with 97% accuracy for the face-to-face battery and 95% accuracy for the telephone battery. These results suggest that it should be possible to diagnose specific language impairment in the adult family members of children with specific language impairment and therefore permit accurate construction of pedigrees for specific language impairment.