This retrospective study was aimed to investigate the association between preoperative left ventricular (LV) cardiac function and the incidence of postoperative pulmonary edema (PE) in patients undergoing carotid endarterectomy (CEA). Most patients undergoing CEA for carotid artery stenosis have concomitant heart diseases, leading to hemodynamic instability that can cause postoperative cardiac complications such as cardiac heart failure. LV diastolic function has recently been recognized as an independent predictor of adverse cardiac events in patients undergoing cardiovascular surgery. We analyzed clinical data from the anesthetic and medical records of 149 consecutive patients who underwent CEA at our university hospital between March 2012 and March 2018. LV systolic and diastolic function were evaluated by ejection fraction and the ratio of LV early diastolic filling velocity to the peak velocity of mitral medial annulus (E/e′). Postoperative PE was diagnosed based on chest X-ray and arterial gas analysis by two independent physicians. Postoperative PE was developed in four patients (2.8%). Patients with postoperative PE were not related to preoperative low ventricular ejection fraction, but had a significantly higher E/e′ ratio than those without PE (P = 0.01). Furthermore, there was an increasing trend of PE according to the E/e′ category. Preoperative LV diastolic function evaluated by E/e′ was associated with the development of postoperative PE in patients who underwent CEA. The results suggest that the evaluation of LV diastolic dysfunction could be possibly useful to predict PE in patients undergoing CEA.