This study examined the usefulness of the Alzheimer's Disease Assessment Scale-Late Version (ADAS-L) for assessing cognitive and behavioral impairment in geriatric schizophrenic patients. Subjects were 339 geriatric schizophrenic inpatients. Discriminant function analyses compared the Mini-Mental State Examination (MMSE) with the ADAS-L as independent variables predicting the level of impairment on the criterion measure, the Clinical Dementia Rating. The ADAS-L surpassed the MMSE at correctly distinguishing severe to profound impairment; the MMSE was superior for identifying absent or questionable impairment. Findings provide evidence for the concurrent validity of the ADAS-L as an instrument for measuring impairment in geriatric schizophrenic inpatients.