The Short Form-36 Health Survey (SF-36) is a widely used measure of health-related quality of life, however, its suitability for frail older persons is not well documented. This study examines the measurement properties of the SF-36 in a frail older patient population. Patients consecutively admitted to two geriatric services (n = 146) were administered the SF-36 and comparative measures on admission and discharge. Internal consistency (0.75-0.91) and test-retest reliability (0.24-0.80) did not meet standards for clinical application of the tool. Four subscales were moderately correlated with comparative measures (Physical Function 0.53 to -0.76; Bodily Pain -0.61; Vitality -0.58; Mental Health -0.63). The results of effect size, standardized response mean, and relative efficiency statistics were consistent in documenting only minimal change for the SF-36 subscales. The SF-36 appears to be reliable and valid, although its ability to monitor clinical change for frail older patients is questionable.