Fatigue, a symptom with many possible causes, is highly prevalent among persons with HIV/AIDS. The causal attributions HIV+ individuals make for their fatigue are important because they largely guide the coping responses they use to manage it. In a study to better understand the symptom appraisal process among 100 HIV+ older adults (50+), 49 participants discussed in depth their experience with fatigue. Many participants felt confused, at least initially, about the source of their fatigue, although most offered their HIV disease as a possible cause. However, many who did so also believed it was caused in part by other, generally less threatening causes, such as age, overexertion, or excess weight. HIV medications and other symptoms or comorbidities were also frequently cited as causes of fatigue. Health care professionals and HIV+ peers often helped to shape or reinforce participants' attributions for their fatigue.