To evaluate a standardized mental status exam's ability to predict activities of daily living (ADLs), Mini Mental Status Exam (MMSE) scores and ADL scores were obtained from 59 patients with progressive dementias of widely varying severity but with no other psychiatric disorders or major medical problems. The MMSE scores explained only about one-third of the variance in both instrumental ADLs and physical ADLs in the whole sample, and the MMSE and ADLs were independent of one another in the less demented half of the sample. This suggests that cognitive losses and functional impairments are two distinct aspects of dementia severity, which must be assessed separately.