It was the goal of this study to examine the ecological validity of a number of measures of mental status for geriatric individuals. Subjects were 40 alert, ambulatory male VA patients. Mental status instruments included the Mini-Mental State Examination (MMSE), the Wechsler Memory Scale (WMS) and the Vocabulary subtest of the WAIS-R. Measures of functional behavior included the Woodcock-Johnson Scales of Independent Behavior (SIB) and the Parachek Geriatric Behavior Rating Scale (PGBRS). Significant relationships were found between the MMSE and the SIB, between the WMS and the SIB, and between the WMS and the PGBRS. It was found that estimation of functional behavior can be enhanced significantly through the use of battery of mental status instruments.