We devised a new leg reposition test, to assess gait and balance in patients with spinal diseases. This study included 344 patients who were scheduled to undergo spine surgery; 14 (4.1%) patients showed positive results. These 14 patients had worse gait status than leg reposition test-negative patients both preoperatively and postoperatively. The leg reposition test is a simple procedure, and requires no specialized equipment. This study showed that the leg reposition test has a strong relation with gait status, and therefore a high clinical significance regarding the assessment of preoperative gait and balance and prediction of postoperative gait status.