Physical inactivity contributes greatly to the health care burden of older adults and is associated with a high prevalence of functional limitations, morbidity, and disability. Rates of physical inactivity are highest among older adults. Older veterans, compared non-veteran older adults, are more likely to be physically inactive and report more limitations in physical function. Increasing physical activity among older veterans is a promising approach to reduce the burden of chronic disease and its associated functional limitations. The purpose of this study is to determine whether a 12-month physical activity counseling program, compared to usual care, improves physical performance in a sample of older veterans The primary physical performance outcome is change in gait speed. Secondary objectives include examination of the effect of intervention between the two groups (intervention and usual care) on physical activity, self-reported physical function, and health-related quality of life. We also will estimate health care costs between the two groups to determine the short-term economic impact of the counseling in the VHA. Design. Randomized controlled clinical trial. Data collection. All consented patients will receive a baseline computer assisted interview and physical performance test to be repeated quarterly for one-year. The primary outcome is change in gait speed, which is highly predictive of subsequent institutionalization and mortality. Secondary outcome measures include: the SF-36 physical function and other relevant subscales, health-related quality of life, physical activity, self-efficacy, and personal functional goals. Differences between groups for non-routine outpatient clinic use and hospitalization will be explored. The cost of providing an intensive intervention (relative to the cost of usual care) will be calculated relative to functional changes between groups. Individuals randomized to the intervention group will receive a physical activity counseling intervention that includes four components. We will measure and assess change at each endpoint (3,6,9, 12, and 24 months) to determine short and long-term efficacy. Secondary analyses will include: (a) effect of intervention on self-reported physical function, physical activity, personal functional goals, and self-efficacy, and (b) comparison of outpatient clinic use and hospitalization costs between treatment arms relative to intervention costs. Duration Four years. Relevance to the VA. Because approximately 50% of veterans over age 74 have a limiting disability, it is imperative to explore strategies that will alter the course of functional decline of our aging veterans.