OBJECTIVE Intraoperative two-dimensional transesophageal echocardiography (2DTEE) is a widely accepted method to guide cardiac valve surgery. The aim of our study was to evaluate the feasibility, effectiveness, and incremental value of intraoperative epicardial real-time three-dimensional echocardiography (RT3DE). METHODS Thirty consecutive patients (18 aortic and 12 mitral valve diseases) underwent intraoperative 2DTEE and RT3DE before and after cardiopulmonary bypass. Five observers compared independently 2DTEE to live and full volume images and to the surgical view, to assess the incremental value of RT3DE in depicting the different anatomic structures. RESULTS Epicardial RT3DE was feasible in all patients. Qualitative evaluation determined RT3DE superiority in depicting aortic cusp morphologic lesions; left ventricular outflow tract spatial relationships with mitral apparatus and aortic root; and both anterior and posterior mitral leaflet scallops, particularly posterior commissure. CONCLUSIONS In our study, epicardial RT3DE has been demonstrated to improve morphologic definition of anatomic valvular lesions and their relationship with cardiac adjacent structures. It may be a valid substitute when the 2DTEE approach is contraindicated, or it could have a complementary role, coupled with 2DTEE, to give additional information for surgical planning.