The invention relates to the use of Roflumilast, Roflumilast-N-Oxide or apharmaceutically acceptable salt of either for the treatment of pulmonaryhypertension. The invention additionally relates to the use of Roflumilast,Roflumilast-N-oxide or a pharmaceutically acceptable salt of either incombination with a PDE5 inhibitor or a pharmaceutically acceptable saltthereof for the treatment of pulmonary hypertension.