The purpose of this study is to replicate and extend earlier work involving cluster analysis of MMPI profiles among persons with chronic low back pain. There are two specific goals. The first goal is to demonstrate the existence in a new sample of four distinct and homogenous profile clusters that have been found in previous research. The second goal is to investigate the relationship of the four profiles to the subjects, self-reported pain history and response to treatment. This study concludes that four distinct MMPI profiles can be identified among chronic low back pain patients. Further, these profiles are the same for males and females, and are the same profiles found in previous research. These profiles are significantly related to subjects' history of behaviors in dealing with pain. However, no relationship to treatment response was found. It was inferred that the MMPI is of value in understanding the nature of patients' pain coping behaviors, but that further research is needed before any statements can be made regarding the utility of the MMPI in understanding their response to treatment.