Happiness and satisfaction with life has emerged as a renewed topic of interest among gerontological investigators. However, the conceptualization of life satisfaction and happiness in advanced later life can present challenges relative to selection of proper measurement instrumentation. This chapter addresses the conceptualization and measurement of life satisfaction and happiness in very old age in three key ways. First, the conceptualization of subjective well-being is addressed in reference to the oldest old. Second, psychometric properties pertaining to past and current use of classical (e.g., Life Satisfaction Index-A), second-generation (e.g., Satisfaction with Life Scale), and domain-specific (e.g., Retirement Satisfaction Index) measures of subjective well-being within old and very old populations is addressed. Third, future directions for the advancement of measurement of subjective well-being in old-old populations are highlighted.