Transabdominal ultrasound in the hydrotechnique (hydrosonography) was compared with endosonography for the locoregional staging of gastric cancer. For this purpose 52 consecutive patients were examined by endosonography (7.5 and 12 MHz) and hydrosonography (3.75 MHz). Forty-nine of the 52 tumors could be examined by endosonography and 41 by hydrosonography. The T-staging accuracy rate of endosonography was 74% and 46% for hydrosonography. Carcinoma of the cardia are often classified as uT3 and hT3 preoperatively and pT2 postoperatively due to infiltration of the subserosal fat. The N-staging accuracy rate of endosonography was 86% and 61% for hydrosonography. Based on these results, transabdominal ultrasound in the hydrotechnique (hydrosonography) cannot replace endosonography in gastric cancer staging. However, when performed in conjunction with conventional ultrasound, hydrosonography provides useful information about the local tumor stage, especially in cases of advanced and stenotic tumors.