Purpose: This study was to determine the effects of a early exercise program on the pain, disability and balance after single-level lumbar discectomy. Methods: Forty patients were randomized into experimental(N=20) and control(N=20) groups. Three days after surgery, patients in the experimental group undertook a 4-week exercise program. Assessments were performed in all patients during the week before surgery and at 4 weeks after. The assessment included measures of back and leg pain(VAS), Oswestry disability index(ODI), stability index(SI) and weight distribution index(WDI). Results: At 4 weeks, VAS, ODI, SI, WDI were significantly reduced in both groups(p<.01). Also the experimental group was significantly reduced back and leg pain(VAS), ODI and WDI were better than the control group(p<.05). Conclusion: It seems that early exercise program is more effective in patients who undergo single-level lumbar discectomy.