The Georgia Centenarian Study examines the biologic, psychologic, and social factors contributing to life satisfaction and successful aging in late adulthood. Three age groups are included, 60 through 69 years, 80 through 89 years, and 100+ years. While the overall theoretical model includes multiple variables, physical health is viewed as critical to successful aging. This article presents an overview of physical health measurement for older persons. Some existing measures of physical health are included in the test battery for the Georgia Centenarian Study; however, the investigators determined the need for the inclusion of a new instrument. This article describes existing measures as well as the rationale and process of development of a new instrument.