Abstract: Low back pain with a very high burden on health care systems, is one of the most common chief complaints of patients in family medicine. One of the leading causes of low back pain is disc degeneration. We designed this study to find any association between smoking and disc degeneration. As a case control study we compared pack years of smoking between patients with disk degeneration and patients without disc degeneration. By reviewing lumbar MRI of 500 patients who were referred to university MRI center we found 51 patients with disk degeneration based on Modic criteria. We restricted our study to male patients who hadn�t history of shift work, drinking alcohol, diabetes, sedentary life style, trauma to low back and family history of low back pain. Also we controlled the effect of age by paired matching of cases and controls. Our sample dropped from 51 cases/controls to 31 cases/controls after controlling mentioned risk factors. Chi square test showed disk degeneration hadn�t significant association with body mass index and having risky job. Logistic regression analysis showed that smoking 1 to 5 pack years (odds ratio= 5.87, 95% CI: 1.60-21.53) and also more than 5 pack year (odds ratio= 6.11, 95% CI: 1.52-24.66) are associated with increased risk of disk degeneration. Health education programs for prevention of low back pain may consider quitting cigarette smoking specially when there is co-morbidity between smoking and other major risk factors for arthrosclerosis.