Schwannoma, which arises from the neural sheath of peripheral nerves, is the most common benign tumor in the retroperitoneum in adults. Complete excision is the treatment of choice for retroperitoneal schwannoma. During surgery, it seems to be unnecessary to identify the small peripheral nerve from which it develops. Keeping a dry field, however, through meticulous control of fine vasculature is of primary importance to avoid inadvertent injury to any of the adjacent organs, large vessels or important nerves. There are few vessels, if any, on the anterior and lateral surfaces of the tumor. Numerous small vessels to and from the tumors are located at its posterior and medial (aortic) aspects, without forming large trunks. Harmonic scalpel may be a good armamentarium in this area. In conclusion, considering such multiple small tumor vessels running adjacent to the aorta, the surgeon should pay close attention to the course of central dissection of these tumors in the retroperitoneum.