Purpose of the study: We conducted a qualitative study of 38 mid-late life volunteers in intensive humanitarian service to ascertain the challenges, personal changes, and benefits they experienced from their volunteer activities. Intensive volunteering was defined as service done on a 24-hr a day basis at a location away from home. Design and Methods: In-depth interviews were conducted by phone or in person with each participant. Couples serving together were interviewed conjointly. Data were analyzed using McCracken's 5-step process for long interviews. Results: Participants described and resolved many challenges including adjustment to new situations and cultures, work-related challenges, and readjustment to home. Consistent with Erikson's descriptions of care, volunteers described benefits of expanded social networks, increased closeness to spouses, and increased compassion and empathy for others. In terms of wisdom, they described altered personal perspectives, with lessened materialism and self-focus, greater appreciation of cultural differences, and finding existential meaning in service. Implications: Because of population aging and social service organizational contraction, humanitarian service organizations may rely more on older volunteers to fulfill their goals. A deeper understanding of the challenges, ways in which they were met, and perceived benefits of later life intensive volunteering can inform organizational efforts to recruit older adults and support them in diverse settings.