To evaluate the impact of single-lung transplantation on right and left ventricular performance and to identify potential preoperative characteristics that could predict postoperative outcome, a large group of patients were retrospectively evaluated by means of serial Doppler echocardiography. Twenty-six of 57 consecutive single-lung transplant patients had satisfactory Doppler echocardiographic studies before and after surgery. A significant reduction in right ventricular diastolic and systolic areas and an increase in right ventricular fractional area were noted after transplantation. The left ventricular contractility remained unchanged. In addition, significant reduction in right atrial area, right ventricular free wall thickness, and tricuspid regurgitation were also seen. Paradoxical septal motion present in eight patients before the procedure resolved in all of them after single-lung transplantation. Transthoracic echocardiography is a useful technique to document improvement in right ventricular function in 63% of patients following single-lung transplantation. Preoperative paradoxical septal motion identifies single-lung transplant recipients who have the largest postoperative right ventricular area reduction and fractional area increase. Alternative imaging modalities should be sought for single-lung transplant candidates in whom conventional transthoracic echocardiography is suboptimal.