The advent of widespread ART provision in low- and middle-income countries requires not just medical attention, but also social and psychological support to encourage and monitor strict adherence to drug regimens. Developing innovative approaches to providing this broad support is a major challenge, especially within the financial constraints of resource-limited countries hardest hit by the epidemic. In this study, we examine the role of older-age parents in monitoring ART treatment and caring for their HIV-infected children and grandchildren in Cambodia. Our results are based on 25 open-ended interviews with older-age parents of people with AIDS (PWHA). A high level of co-residence when PWHA become ill and a sense of parental responsibility and emotional attachment facilitate high parental involvement in their children's and grandchildren's illness, care and treatment. Our interviews indicate that parents play an important role in encouraging their children to get tested and to access treatment if they test positive. They consistently monitor antiretroviral therapy (ART) adherence and opportunistic infections and remind PWHA to attend medical appointments and support-group meetings. Parents also provide for the nutrition and hygiene of PWHA essential to the success of ART treatments. We find that despite low levels of education, older parents were able to express clear, correct and detailed knowledge of complicated ART treatment regimens, nutrition and hygiene. Overall, our findings show that older parents play a pivotal role in care and treatment if they are provided with proper resources and training and have the ability to understand the necessity and details of ensuring strict adherence to medications. Based on these results, we suggest that explicitly including older parents in policy and programs for care and treatment would allow Cambodia and other countries to take advantage of this unique and effective but overlooked asset in AIDS care and treatment.