This article will provide an overview of real time 3-dimensional (3D) echocardiography (RT-3D) in evaluation of patients with heart disease. We will briefly describe the technique and our experience in its clinical applications in patients with coronary artery disease, left ventricular apical thrombi, mitral stenosis and its role in guiding intracardiac catheter placement. Our extensive experience with application of RT-3D during dobutamine stress and during supine bicycle exercise indicates the technique is sensitive in detection of ischemia. RT-3D has been valuable in clearly identifying left ventricular apical thrombi in patients in whom 2-dimensional (2D) echo cannot firmly establish their presence or absence. We have utilized RT-3D in guiding myocardial biopsy in heart transplant patients and in precisely measuring mitral valve area before and after balloon valvuloplasty. RT-3D technique continues to evolve and should play an important role in assessment of patients with heart disease.