We know that social psychologic factors important to make a decision on characteristic of back pain and prognosis. These facters have difficult to diagnosis of back pain and being protract the treatment session and which bring about a social problem caused the impairment compensation. Clinically, twenty low back pain patients, 8 organic pain group and 12 functional pain group have completed the MMPI(Minnesota Multiphasic Personality Inventory) and the results were as follows: l)Mean MMPI T-score of Hypochondriasis was 56.60(12.39, that of Depression was 57.95(7.71, and that of Hysteria was 57.50(7.15. and those of other scales were within normal range near to 50. 2)there was no significant difference between male and female groups on MMPI scales 3)The MMPI T-score of organic group was significantly higher than that of functional group on Hypochondriasis and Hysteria scale.