Purpose : The purpose of this study was to investigate the effects of joint mobilization on the rang of motion and pain of patient with chronic low back pain. Methods : The subjects were consisted of thirty patients with chronic low back pain(19 females, 11 males ; mean aged 59.93) from 50 to 71. All subjects randomly assigned to the modalities treatment group, joint mobilization group. Modalities treatment group received hot pack used thermal therapy for 20minutes and ICT used electrical therapy for 15minutes, joint mobilization group received modalities treatment with sustained natural apophyseal glides(SNAGS) techniques of Mulligan for 10minutes per day and three times a week during 2 weeks period. Visual Analogue Scale(VAS) was used to measure subjective pain level. Remodified Schober test(RST) was used to measure range of motion of lumbar spine. All measurements of each patients were measured at pre-treatment and 2 weeks post-treatment. Results : The results of this study were summarized as follows : 1. VAS was joint mobilization group showed significantly decreased more than modalities treatment group (p<.05). 2. The lumbar flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 3. The lumbar extension range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 4. The lumbar left lateral flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). 5. The lumbar right lateral flexion range of motion was joint mobilization group showed significantly decreased more than modalities treatment group(p<.05). Conclusion : These data suggests that SNAGS of Mulligan is beneficial treatment for chronic low back pain.