Our study was undertaken in order to evaluate hemodynamic effects of intravenous administration of Reproterol in patients with chronic obstructive lung disease (COLD). Reproterol is a monomulecolar combination of catecholamine and theophilline. Diastolic pulmonary pressure and wedge pressure decreased 20 minutes after Reproterol while total pulmonary resistances were reduced 10 minutes after drug administration; sistolic pulmonary pressure and cardiac index increased only after 10 minutes; heart rate increased until 15th minute. Reproterol, as a catecholamine-theophylline combination, has an additional site of action over and above the pure catecholamine effect owing to inhibition of phosphodiesterase; so an increase in cAMP content is achieved either by increasing the synthesis or by blocking the breakdown. Our results assess that Reproterol has a beneficial effect on pulmonary hemodynamics in COLD.