²³Na MRI may allow distinction of normal and ischemically injured myocardium. The aim of this study was to optimize ²³Na MRI of the human heart by improvement of spatial resolution and ECG‐triggering and to measure the signal/noise of blood and myocardium and the myocardium/blood signal ratios in a volunteer study. A spoiled gradient echo sequence was developed on a 1.5T scanner equipped with a ²³Na heart surface coil. 3D short axis ECG‐triggered ²³Na MRI was performed in 10 healthy subjects. The signal/noise of myocardium and blood were 8.2 ± 0.7 and 18.3 ± 1.3, respectively, signal ratio myocardium/blood was 0.44 ± 0.03. This value is in good agreement with the theoretical value of 0.45. ECG gated 3D ²³Na MRI of the human heart is feasible with sufficient spatial resolution and signal/noise ratio. Magn Reson Med 45:164–166, 2001. © 2001 Wiley‐Liss, Inc.