Over the past decade, the importance of acceptance of chronic pain has been demonstrated. Acceptance has often been assessed using the 20-item. two-factor Chronic Pain Acceptance Questionnaire (CPAQ; McCracken, Vowles, Eccleston, Pain 2004;107:15966). This two-factor model has been supported but awaits further confirmation. The present investigation Sought to address this issue in two large samples of pain suffers. Exploratory factor analyses (N = 333) examined a number of solutions, ranging from two to five factors. Evaluation indices provided clear Support for a 20-item, two-factor solution. Confirmatory factor analyses, using the second sample (N = 308), examined a number of models. Fit indices demonstrated that the model identified in the exploratory analyses had the best fit. Finally a series of cluster analyses were performed using a combined sample (N=641). Results indicated three Clusters: one with high scores oil both subscales (n=146), one with low scores oil both subscales (n = 239), and one with discrepant scores that were high on the Activity Engagement subscale and low on the Pain Willingness subscale (n = 286). Follow-up analyses indicated significant differences among the clusters across multiple measures of functioning. The Cluster with low CPAQ scores reported more difficulties in comparison to the group With high scores, while the group with discrepant CPAQ scores generally reported difficulties that fell in between. These results provide further support for the 20-item, two-factor CPAQ and indicate that it is both theoretically and practically useful. (c) 2008 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.