Several cardiorespiratory diseases can complicate human immunodeficiency virus infection. Primary pulmonary hypertension is a rare clinical disorder which carries a bad prognosis. More than 90 cases of HIV-associated primary pulmonary hypertension have been reported to date. Although its pathogenesis remains unknown, some evidence suggests a possible role for the virus itself in its development. Genetic susceptibility may also be implicated. The clinical and histopathologic features of this entity do not differ from those of classic primary pulmonary hypertension. The diagnosis requires a high degree of clinical suspicion and a careful evaluation to rule out causes of secondary pulmonary hypertension. In addition to supportive measures, anticoagulation and vasodilators have been used to treat this disorder, although sufficient data regarding long-term results with these therapies are lacking.