The present study was designed to test a number of hypotheses derived from personal construct theory and pain theories by means of the Rep Grid technique with chronic and acute low back pain patients. The subjects were 22 low back pain patients. The instruments were the 12 constructs × 12 elements Rep Grid, a Low Back Pain Questionnaire, the SF McGill Pain Questionnaire, and the BDI. The data were analysed by the INGRID 99 program. The results were as follows: (1) For chronic low back pain patients, self now offered more implications than self without pain and ideal self. (2) Chronic lower back pain patients have difficulty in expressing emotions. Anger, depression and sensitivity toward others are less available to them. suggesting a low level of awareness. (3) For chronic low back pain patients, pain was not superordinate, but they accepted self now with pain. Finally, the results were discussed with reference to the literature and suggestions are made for future research.