Recently, ultrasonography has been widely used to evaluate varicocele. However, it is difficult to obtain reproducible scrotal images with a hand probe in the standing position. We, therefore, applied the water bag technique during ultrasonographic examination of the scrotal contents in the supine position. The ultrasonographic images thus obtained were compared with physical findings and scrotal scintigraphic findings. Forty-five varicocele patients diagnosed by palpation and ultrasonography were enrolled in this study. An ultrasonographic examination through a water bag in the supine position has the following advantages 1) it is easy to perform and stable images are obtained, 2) varicoceles that are not palpable can be detected and 3) examinations can be repeated both pre- and postoperatively. Of the 45 patients, 39 and 41 had positive findings on the ultrasonographic images and physical examinations, respectively. Four patients had negative findings on physical examination but positive findings on the ultrasonographic images. Thus, ultrasonographic images through a water bag in the supine position proved to be a useful method of confirming the hemodynamics in varicoceles.