Purpose: The purpose of this study was to document the benefits of volunteering perceived by older adults and to explain variation in these self-perceived benefits. Design and Methods: This is a quantitative study of 13 volunteer programs and 401 older adults serving in those programs. Program directors completed telephone interviews, and older volunteers completed mailed surveys. Volunteer-level and program-level data were merged. Results: Older volunteers reported a wide variety of benefits to the people they served, themselves, their families, and communities. More than 30% reported that they were "a great deal better off" because of volunteering, and almost 60% identified a benefit to their families. When considering only individual characteristics, lower-income and lower-educated volunteers reported more benefit. Yet, aspects of the volunteer experience, like amount of involvement, adequacy of training and ongoing support, and stipends, were more important in understanding who benefits from volunteering. Implications: These findings suggest that characteristics of volunteer programs can be strengthened to maximize the benefits of volunteering to older adults. These characteristics are more mutable by public policies and organizational procedures than individual characteristics. Focusing on the recruitment of lower socioeconomic status older adults may result in an increase in benefits from the growth of volunteering.