Many daily activities cause acute elevations of intra-abdominal pressure (IAP). In portal hypertensive cirrhotic patients, increased IAP increases absolute portal pressure and azygos blood flow, suggesting that it may have detrimental consequences at the esophageal varices. The aim of this study was to investigate the effects of increased IAP on variceal pressure, size, and wall tension. Endosonography and a noninvasive endoscopic pressure gauge were used to measure variceal pressure, radius, wall tension, and volume in baseline conditions and after increasing IAP by 10 mm Hg using an inflatable girdle in 14 patients with cirrhosis and esophageal varices. Increasing IAP markedly increased variceal pressure (from 13.3 ± 4.2 to 17.4 ± 4.6 mm Hg; P = .0001) and radius (from 2.9 ± 1.0 to 3.9 ± 1.1 mm; P = .0001). Consequently, wall tension dramatically increased (from 38.7 ± 13.6 to 65.9 ± 23.8 mm Hg · mm, +78%; P = .0001). Variceal volume increased significantly from 1,264 ± 759 to 2,025 ± 1,129 mm3 (P = .0001). In conclusion, in portal hypertensive cirrhotic patients, increases in IAP have deleterious effects on variceal hemodynamics, markedly increasing the volume, pressure, and wall tension of the varices. Increases in IAP may contribute to the progressive dilatation that precedes the rupture of the varices in portal hypertension.