Due to advances in treatment, people with HIV are living longer and developing disabilities related to the virus, adverse side effects of medications, and aging. Illness-related uncertainty has been shown to contribute to disablement; however, there is little understanding of the uncertainties related to aging with HIV. The purpose of this research was to describe the contribution of uncertainty to the disability experienced by older adults living with HIV. Forty-nine men and women living with HIV and 50 years or older participated in in-depth qualitative interviews exploring various aspects of social participation and disability. Transcriptions of the interviews were analyzed using a grounded theory approach. Age-related uncertainties were described in the following themes: source of health challenge; health providers' age-related knowledge and skills; financial uncertainty; transition to retirement; appropriate long-term housing, and uncertainty over who would care for them. While not directly attributable to aging, the episodic nature of HIV left many with uncertainties related to when their next episode of illness would occur and often resulted in an inability to plan in advance. Results highlight the need to focus on the notion of successful and positive aging with the view to identifying effective interventions that reduce disability and enhance the overall health of older adults with HIV. This work builds on previous studies highlighting the role of uncertainty in the disability experience by identifying age-related components specific to older adults aging with HIV.