Introduction.-Multiple factors might affect the velocity recording in the celiac artery (CA), causing a compression syndrome. Reports that focused on the phase of respiration found that the CA is highly compressed during the phase of expiration. Few reports in the literature have focused on body position during Doppler scanning of the CA. The aim of this study was to evaluate the effect of patient position as well as the phase of respiration on velocity recording in the CA.Methods.-Thirty male subjects were entered prospectively into the study. Peak systolic velocity and vessel diameter at the origin of the CA at different body position and different phases of respiration were recorded by the use of duplex ultrasound while the subject was fasting.Results.-There were 30 healthy men; their average age was 25.5 ± 5.30 (±SD, years), and their average body mass index was 24.8 ± 3.1 (±SD, kg/m 2 ). The average diameter of CA in supine position and expiration was 0.70 ± 0.10 (±SD, cm), and the average peak systolic velocity was 111.2 ± 29.7 (±SD, cm/s). Moreover, the average diameter of CA in standing position in expiration was 0.75 ± 0.10 (±SD, cm), and the average peak systolic velocity was 96.8 ± 25.2 (±SD, cm/s). Paired Student t test for the effect of body position and phase of respiration in the peak systolic velocities and the diameter of the CA was performed and demonstrated statistical signifi cance (p < 0.05).Conclusion.-The CA peak systolic velocity varies between 2 positions in healthy young men, which may have implications for disease detection and needs further study.