This article examines the relationship of obesity and arthritis to length of life and length of disabled life in older American men and women. Secondary data analysis is conducted on three waves of the Asset and Health Dynamics Among the Oldest Old (AHEAD) survey (n = 7,381). Using integrated Markov chains, total, active, and disabled life expectancy in Americans aged > or =70 is estimated, with and without obesity and arthritis. Results indicate that neither obesity nor arthritis is related to the length of life for older men and women, alone or in combination. However, both conditions are significantly individually associated with increased length of disabled life in older men (1.4 years attributable to obesity; 1.2 years to arthritis at age 70; P < 0.05) and women (1.7 years attributable to obesity; 2.1 years to arthritis at age 70; P < 0.05). In addition, the combination of the two is significantly related to decreased active life, with nearly 50 and 60% of remaining life for 70-year-old men and women lived with disability, respectively (P < 0.05). Coupled with the fact that both obesity and arthritis are growing in prevalence, these findings represent one of the few clearly negative health trends in older adults today. These results should provide incentives for health-care professionals to make concerted efforts to address both conditions in clinical settings.