Emphysema is frequently complicated by the presence of heart disease other than cor pulmonale. This association raises many problems in diagnosis and treatment. One is frequently confronted with a patient complaining of dyspnea who is noted to have a barrel chest, distended neck veins, palpable liver, hyperresonant percussion note, pulmonary râles, loud pulmonic second sound, and ankle edema. These findings might be due either to diffuse obstructive pulmonary emphysema or to left ventricular failure with simple, coincident, nonsymptomatic senile emphysema. The differentiation is obviously important. In this discussion, clinical guide lines are presented which are helpful in making this distinction. Pertinent points in the history include orthopnea, paroxysmal nocturnal dyspnea, exposure to respiratory irritants, and the duration and course of the symptomatology. Helpful physical findings include diaphragmatic excursion, retraction of rib margins, type and location of the cardiac impulse, gallop rhythms, pulsus alternans, characteristic râles, mechanismal disturbances, and type of neckvein distention. Laboratory data of importance are the electrocardiogram, chest x-ray film, circulation time, blood-gas determinations, and pulmonary function studies. When emphysema and heart disease coexist, problems in treatment are compounded. Problem areas noted in this discussion include the use of: sedatives, analgesics, and tranquilizers; bronchodilators; antibiotics and anticoagulants; oxygen therapy; phlebotomy; cough suppressants; diuretics; adrenal steroids; fluid and electrolyte therapy; compression belts; antihypertensive agents and digitalis.