Experimental evaluation of new therapy for congestive heart failure has been hampered by the lack of a simple and reliable animal model of heart failure. This study was undertaken to develop a canine model of chronic left ventricular dysfunction. A left thoracotomy was performed in 9 adult mongrel dogs. A 1.5-mm Silastic (Dow Corning) catheter with an attached subcutaneous access port was positioned in the left main coronary artery. Six animals received five weekly infusions of Adriamycin (doxorubicin hydrochloride) (10 mg/wk), and 3 received saline solution. Hemodynamic studies were performed before insertion of the catheter and 2 weeks after completion of the infusions. In animals that received Adriamycin, rest ejection fraction declined from 0.54 ± 0.03 to 0.35 ± 0.03, cardiac output fell from 5.6 ± 0.6 to 3.9 ±0.5 L/min, and left ventricular end-diastolic volume increased from 76 ± 9 to 99 ± 12 mL (p < 0.05). There was a small increase in right atrial pressure (2.7 ± 1 versus 5.7 ± 1 mm Hg) but no change in right ventricular ejection fraction (0.31 ± 0.04 versus 0.30 ± 0.03). In no animal did alopecia, weight loss, neutropenia, or anemia develop. Histological changes consistent with Adriamycin-induced cardiac toxicity were found in each dog. No significant hemodynamic or histological changes occurred in the control animals. Administration of Adriamycin into the left main coronary artery causes left ventricular dysfunction without resulting in systemic side effects or compromising right ventricular function. This animal model could be used to evaluate the effects of new possible therapy, such as cardiomyoplasty, on left ventricular failure.