Objective: The present study investigated the effects of both catastrophizing and the pain willingness component of acceptance on interference in daily activities and task performance during experimentally induced ischemic pain. In addition, the potential moderating role of pain willingness on the relationship between catastrophizing and degree of pain interference was also examined. Design: Sixty-seven persons with chronic low back pain completed measures of catastrophizing, acceptance, and daily pain interference. Participants underwent an ischemic pain induction procedure during which a Stroop-like task was administered. Main Outcome Measures: Self-reported pain interference and observed performance on a Stroop-like task during induced pain. Results: The pain willingness component of acceptance and catastrophizing both contributed significantly to self-reports of pain interference. However, levels of pain willingness had an effect much stronger than the negative effects associated with catastrophizing with respect to observed pain interference during induced pain. Results also indicated that pain willingness serves as a moderator in the relationship between catastrophizing and task performance during induced pain. Conclusion: The pain willingness factor of acceptance and catastrophizing both appear to be strong predictors for self-reported pain interference. During an objective assessment of pain interference, however, pain willingness shows a stronger effect and attenuates the negative impact of catastrophizing on task functioning. © 2010 American Psychological Association.