The beneficial effects of a strength exercise program and a combined exercise program of strength training plus walking were examined in overweight with chronic back pain patients. The participants were randomly placed in the strength exercise group (SEG, n=15), combined exercise group (CEG, n=15), and control group (CG, n=6). All subjects performed exercise twice per week, 50 min per session with a professional instructors for 12 weeks. In order to evaluate exercise intervention effects, lumbar function was measured by back strength and flexibility. Roland-Morris disability questionnaire (RMDQ) and visual analogue scale (VAS) were used to evaluate pain level. Fat and muscle mass were measured to compare body composition changes. All measurements were performed before and after 12 weeks of exercise program. Lumbar function: Back strength was significantly different over time, and significant time×group differences were found between SEG and CG and, CEG and CG. Pain disorder degree: VAS showed a significant group difference, and significant time×group differences were shown between SEG and CG, and CEG and CG. Also, RMDG showed a significant difference between CEG and CG. Body composition: Fat mass was significantly different over time×group between SEG and CG. In conclusion, participating in strength and walking exercises were beneficial to improve lumbar function. Also, the combined exercise program was more effective for reducing pain levels than the strength exercise. Finally, fat mass was reduced in this study and this may play a possible role in the improvement of lumbar function and reduction in low back pain.