To evaluate isolated single lung perfusion with chemotherapy in a rat lung metastasis model, we developed a model of in vivo isolated single lung perfusion. Twenty male rats were anesthetized with pentobarbital sodium (50 mg/kg) and intubated endotracheally. A left thoracotomy was performed with an operating microscope (x16 magnification), the left pulmonary artery was cannulated, and a left pulmonary venotomy was performed. Isolated left lung perfusion was performed for 10 min at 0.5 ml/min with heparinized whole blood (n = 10) or 0.9% normal saline (n = 10). Pulmonary vein effluent was collected by suction. Nineteen of the 20 (95%) animals survived isolated left single lung perfusion. Twenty-one days after isolated left lung perfusion right pneumonectomy was performed. Fifteen of the 19 animals (78%) survived right pneumonectomy. Postoperatively, animals that survived surgery recovered preoperative body weight. In vivo isolated single lung perfusion in rats is feasible with low mortality and morbidity and may be useful in the study of isolated perfusion with chemotherapy and in diverse physiological and pharmacological experiments.