Reliability and validity of three mental status questionnaires—the Short Portable Mental Status Questionnaire, Mini-Mental State Examination, and Cognitive Capacity Screening Examination (CCSE)—were assessed using 66 elderly (age ≥ 65 years) hospitalized medical-surgical patients. Internal consistency as well as content, criterion-related, and construct validities were examined. The CCSE was found to be the most valid and reliable measure of mental status in this patient population. Implications of the findings regarding selection of mental status questionnaires for differing purposes are discussed.