Pulmonary arterial hypertension (PAH) is an infrequent but nevertheless serious life-threatening severe complication of HIV infection. As a result of its non-specific presentation, PAH tends to be recognized at a late stage of the disease, and patients have generally been in New York Heart Association functional class III or IV by the time of diagnosis. The widespread use of HAART has improved overall survival in HIV-infected individuals, but its effect on the incidence and severity of PAH in particular has been controversial. Data on the long-term impact of HAART on the course of PAH and patient survival in this context have been lacking. This article presents key data from two recent major European studies (the Swiss HIV Cohort Study and a prospective French national study) investigating the prevalence of PAH in the HIV-infected population and the effect of HAART on the long-term course of the disease. Data from these large studies do not suggest that HAART has a major effect on the course of PAH or on survival in these patients. Although there is evidence that new cases of PAH are declining, the overall prevalence is currently similar to the pre-HAART era, and there is still a significant number of HIV-infected individuals who have or are at risk of PAH. Given recent improvements in the treatment of PAH, the early recognition of these individuals is essential.