Stroke occurring in the human immunodeficiency virus (HIV) infected patient is a frequent clinical challenge for clinicians working in regions with a high prevalence of HIV. Is the stroke a co-occurrence of two common conditions, or is it the direct or indirect result of the HIV infection and, if so, how? HIV infection causes stroke by predisposing to opportunistic infections such as tuberculosis and fungal meningitis, by increasing cardioembolic stroke due to direct cardiac involvement with HIV, possibly by interfering with blood coagulation through antiphospholipid antibodies or reduced protein S, or by causing an arteriopathy. In the paper by Tipping and colleagues1 in this issue of J Neurol Neurosurg Psychiatry, the authors describe their experience of HIV associated stroke …