Pulmonary hypertension (PH) is a serious disorder with high morbidity and mortality rate. Evidence is accumulating to suggest that inflammation plays a significant role in the pathogenesis of PH. Endothelial cells play an important role in inflammation and immune reactions, and inflammatory cytokines cause endothelial dysfunction. Endothelial dysfunction is a hallmark of PH, consisting of reduced availability of vasodilators and antiproliferative factors and increased production of vasoconstrictors and vascular proliferative factors. Up-regulation of inflammatory cytokines and perivascular inflammatory cell infiltration have been detected in the lungs of patients with idiopathic PH. Prevalence of PH in patients with systemic inflammatory diseases is well documented. Interestingly, a significant loss of endothelial caveolin-1, a potent immunomodulator and an inhibitor of cell proliferation, has been reported in human and experimental forms of PH. Reduction in the expression of caveolin-1 is known to result in the removal of antiproliferative activities, thus, leading to deregulated vascular cell proliferation. This article summarizes the roles of inflammation and endothelial caveolin-1 and their possible interrelationship in PH.