The aim of this study was to evaluate the usefulness of an imaging technique that takes into account the effect of posture change on the stomach in transabdominal ultrasonography (US). A total of 240 adult patients (healthy subjects) underwent gastric US. In all subjects, the lesser curvature of the stomach (LCS) and left liver were measured in two different positions [left lateral decubitus (LLD) and supine]. The maximal length of the LCS was defined as the measured range between the cardial orifice and the left liver tip. The anteroposterior length (L1) and maximal longitudinal length (L2) of the left liver were determined on epigastric longitudinal scans. The mean LCS in the supine and LLD positions was 90.2 +/- 34.7 and 124.4 +/- 44.4 mm, respectively. The mean L1 in the supine and LLD positions was 54.0 +/- 12.7 and 65.6 +/- 14.4 mm, respectively. The mean L2 in the supine and LLD positions was 84.3 +/- 18.5 and 107.0 +/- 25.8 mm, respectively. The results for the measured LCS, L1, and L2 differed significantly between the supine and LLD positions (P < 0.05). This study demonstrated that the LCS could be clearly visualized on longitudinal scanning in the LLD position. Therefore, this position may potentially be more useful for gastric US, even in view of the limitations of this approach.