ABSTRACT Although ablation of the greater splanchnic nerve is now being used to treat some patients with heart failure, the anatomical relationships between this nerve and the adjacent posterior intercostal veins used for the procedure are not well elucidated. Therefore, the present anatomical study was performed. The anatomy and relationships of the right GSN and the azygos vein were investigated in 50 adult anatomical donors. In the supine position, the anterior wall of the thorax was removed, and the relationship between the azygos vein and its tributaries and the overlying GSN was observed and documented with quantitation of the distances between these structures. At the T7, T8, and T9 vertebral levels, the mean distance between the GSN and the azygos vein was 3.05, 2.35, and 1.62 cm, respectively. We found that the closest distance between the GSN and the azygos vein was at the T9 vertebral level, with a mean distance of 1.62 cm. Therefore, for the shortest distance between vein and GSN, this level should also be considered for ablation level. Such additional anatomical data can help improve patient outcomes and decrease the complication rates of this procedure.