Persistence of chronic renal failure in patients with renal hyperparathyroidism occasionally causes graft-dependent recurrence of hyperparathyroidism after total parathyroidectomy with autotransplantation. The graft should be removed, however, when hyperparathyroidism recurs in these patients. The graft is easily located if it swells enough to be palpable. If the graft is small, however, its position can be roughly determined using preoperative imaging, and tissues surrounding the graft can be dissected by determining their location with macroscopy. Because tissues are brittle and tend to bleed in patients with chronic renal failure, exploration of the graft can seriously damage the surrounding tissues. We operated on a man aged 57 years in whom graftdependent hyperparathyroidism had recurred. Intraoperative ultrasonography was used in addition to the conventional method, in which the graft is located using manipulation and the naked eye. Ultrasonography showed small impalpable grafts as hypoechoic masses in the muscle of the forearm. Injury of vessels surrounding the small graft was prevented, and damage to the surrounding tissues was minimized. The results of color Doppler ultrasonography that revealed hypervascularity of the graft before surgery are also reported. We conclude that graft exploration using intraoperative ultrasonography as a guide could prove useful in detecting small impalpable grafts without damaging the surrounding tissues.