We developed a novel prospective respiratory motion compensation algorithm, Heart-NAV, for free-breathing retrospective electrocardiogram (ECG)-gated 3D-cine steady-state free precession whole-heart magnetic resonance imaging. In 10 patients, there was good agreement between the 3D-cine and conventional breath-hold 2D-cine imaging measurements of ventricular volumes. The mean scan time for the 3D-cine acquisition was 5.9±2.7 minutes. Advantages of the Heart-NAV approach include real-time motion correction allowing for immediate in-line image reconstruction, compatibility with a variety of k-space filling approaches, and utilization of standard scanner hardware/software. Such a 3D-cine approach eliminates the need for breath-holding and simplifies planning for ventricular function assessment.