The prevalence of pulmonary hypertension in interstitial lung disease (ILD) is high (30-40%). However, diagnosis of pulmonary hypertension in ILD is often delayed. Pulmonary hypertension can occur in the absence of advanced pulmonary dysfunction or severe hypoxia and is associated with a worse prognosis. A number of pathogenic mechanisms such as oxidative stress, cytokines, and the endothelin system have been implicated in remodeling of both the lung parenchyma and the vessels. In addition, hypoxic vasoconstriction, vascular destruction and progressive fibrosis play an important role. Since clinical signs are often non-specific echocardiography, radiology and laboratory parameters such as NT-proBNP may be helpful. However, the definitive diagnosis of pulmonary hypertension is still confirmed by right heart catheterization. Treatment options of pulmonary hypertension in ILD are limited to the treatment of the underlying diseases. Newer vasodilating drugs may improve the prognosis but have first to be evaluated in clinical trials. Lung or lung and heart transplantation is the therapeutic option in end stage disease.