BACKGROUND: Monitoring and documenting the mental status of older patients transferred between providers or facilities is important because mental status change can be a sign of acute disease and mental status abnormalities necessitate specific approaches to care. OBJECTIVES: To identify patient and illness factors associated with presence of a mental status description in inter-facility transfer documents and to describe the content and concurrent validity of transfer mental status descriptions when they occur. DESIGN: Retrospective study. PARTICIPANTS: Individuals transferred between 5 long-term and 2 acute care facilities in an urban setting. MEASUREMENTS: Trained research personnel reviewed hospital and nursing home medical records and inter-facility transfer documents. Mental status descriptions in transfer documents were coded as abnormal or normal within 5 domains: alertness, communication, orientation/memory, behavior, and mood. Descriptions were compared with mental status items in the nursing home Minimum Data Set and in a transfer communication checklist. RESULTS: In all, 123 nursing home residents experienced 174 hospital admissions. Mental status descriptions were present in 69% of transfer documents, A total of 67% of patients missing a transfer mental status description upon nursing home-to-hospital transfer had dementia. Factors associated with presence of a transfer mental status description were urgent transfer, nursing home of origin, and among patients without dementia, greater cognitive impairment. When present, a mean of 1.47 (SD = 0.81) cognitive domains were documented in transfer mental status descriptions. Agreement between transfer mental status descriptions and comparison sources was fair to good (kappa = .31 to .73). CONCLUSION., Mental status documentation during transfer of older adults between nursing home and hospital did not identify all patients with dementia and did not completely characterize patients' cognitive status.