Despite the recognized benefits of regular physical activity, older adults remain among the most inactive segments of the U.S. population. A number of studies have demonstrated the health impact and resultant reduction in chronic disease risk achieved by improving physical activity patterns. Effective telephone-based counseling approaches for promoting and sustaining regular physical activity among older adults have been developed and validated. Such mediated interventions provide a level of individual tailoring and ongoing support to long-term adherence, while allowing for ongoing program delivery that is more flexible, convenient, and potentially lower-cost than face-to face program delivery formats. Telephone-based delivery format also allows for potentially greater reach into segments of the older population that may find it difficult or unappealing to come to community settings on a regular basis.