Degenerative arthritis of the lumbar spine is one of the main causes of the low back pain over the fifth decade of life. Nowadays, it seems that the number of obese person increases gradually and the role of Obesity in the development of articular degeneration remains controversial. The authors studied 100 cases of the primary degenerative arthritis of the lumbar spine clinically and statistically and compared 50 cases among these with 2 control groups, with and without low back pain, from Mar. 1982 to Sep. 1982. The results were as follows: 1. Among the patients with the degenerative arthritis of the lumbar spine, the ratio of male to female was 1:4, and the age group with the highest frequency was the 6th decade (47%) 2. 44% was obese in the arthritis group and 26% in the control group with low back pain and 12% in the control group without low back pain. 3. The relative risk of the hypothesis that the arthritic patient is obeser than the patient with low back pain but without degenerative changes on X-ray was 2.3, but the hyposthesis was proved to be statistically insignificant. The relative risk of the hypothesis that the arthriticpatient was obeser than the patient without low back pain and degenerative changes on X-ray was 6.3 and proved to be statistically significant.