Objective: The Purpose of this study is the factive and descriptive research to identify the factors affecting the functional disability of the chronic low back pain patients. We investigated the effect of ODI by the Questionnaire and questioned an 70 patients who were back pain unit at G university hospital in D city from March to May, 2007. The functional disorder in this study were based on the Oswestry Disability Index(ODI) lower back pain disability questionnaire by fairbank(1980), and these data were proceeded by using SPSS/WIN version 10.0. Result: 1. The functional disorder in accordance with age, gender, academic background, occupation, diagnosis, pain cause, pain experience, treatment duration had no significantly similar difference statistically(p>0.05). 2. The functional disorder in accordance with duration of painful generation had statistically significance(P<0.05). Conclusion: we could verify that duration of painful generation affect on the factors affecting the functional disability of the low back pain patients.