The number of human immunodeficiency virus (HIV)–infected outpatients is growing rapidly because of the widespread use of antiretroviral therapy, earlier recognition of HIV infection and prophylaxis, and earlier treatment of opportunistic infections. 56 As a result, new HIV-associated medical problems are being encountered with increasing frequency. Among the most important of these are chronic and recurrent sinusitis. Based on several prospective studies, the incidence of sinusitis in HIV-infected patients is estimated to be as high as 60% to 80%. 27,53 In addition, HIV-infected patients may have an atypical presentation of sinusitis that makes recognition difficult for many practitioners. Because of the associated immunodeficiency in HIV infection, sinusitis often tends to be more severe and difficult to treat than in non–HIV-infected subjects. For these reasons, sinusitis has become a major source of morbidity in HIV-infected patients and is likely to become more of a problem for as long as the HIV epidemic persists. This article reviews the current state of knowledge about sinusitis in HIV infection, including its epidemiology, clinical presentation, pathophysiology, and current recommendations for treatment and management.