Acceptance of pain and other associated negative private experiences has received increasing attention in recent years. This approach is in stark contrast to the traditional approach of reducing or controlling symptoms of pain. The empirical support for treatments emphasizing exposure and acceptance, such as Acceptance and Commitment Therapy, is growing. However, to date, few instruments exist to assess the core processes in these types of treatments. This study describes the development and preliminary validation of the Psychological Inflexibility in Pain Scale. Principal components analysis (PCA) suggests a 2-factor solution with a total of 16 items measuring avoidance of pain and cognitive fusion with pain. Results also indicate adequate reliability and validity for the scale. Implications of these findings for clinical assessment, as well as for research on pain related disability, are discussed along with suggestions for further research in this area.