Objective: Few studies have prospectively evaluated the utility of geriatric assessment tools as predictors of mortality in the oldest population. We investigated predictors of death in an oldest-old cohort after 3 years of follow-up. Methods: The Octabaix study is a prospective, community-based study with a follow-up period of 3 years involving 328 subjects aged 85 at baseline. Data were collected on functional and cognitive status, co-morbidity, nutritional and falls risk, quality of life, social risk, and long-term drug prescription. Vital status for the total cohort was evaluated after 3 years of follow-up. Results: Mortality after 3 years was 17.3%. Patients who did not survive had significantly poorer baseline functional status for basic and instrumental activities of daily living (Barthel and Lawton Index), higher co-morbidity (Charlson), higher nutritional risk (Mini Nutritional Assessment), higher risk of falls (Tinetti Gait Scale), poor quality of life (visual analog scale of the Quality of Life Test), and higher number of chronic drugs prescribed. Cox regression analysis identified the Lawton Index (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.73-0.89) and the number of chronic drugs prescribed (HR 1.09, 95% CI 1.01-1.18) as independent predictors of mortality at 3 years. Conclusions: Among the variables studied, the ability to perform instrumental activities of daily living and using few drugs on a chronic basis at baseline are the best predictors of which oldest-old community-dwelling subjects survive after a 3-year follow-up period.