BACKGROUND: Catastrophizing plays an important role in models of pain chronicity, showing a consistent correlation with both pain intensity and disability. It is conceivable that these associations are mediated or confounded by other psychological attributes. OBJECTIVE: To examine the relative influence of catastrophizing and other psychological variables on pain and disability in patients with chronic low back pain. METHODS: Seventy-eight patients completed the Pain Catastrophizing Scale, Roland Morris Disability Questionnaire, Fear-Avoidance Beliefs Questionnaire (work/activity), Modified Somatic Perception Questionnaire, Modified Zung Depression Scale, and Pain Intensity scale. RESULTS: Catastrophizing was significantly correlated with both Pain intensity and Roland and Morris Disability, and with all other psychological variables (all p < 0.001). However, multiple regression analyses showed that Catastrophizing explained no significant variance in Pain intensity beyond that explained by the unique contributions of Modified Somatic Perception and Fear-Avoidance Beliefs (work) and explained no further variance in Disability beyond that explained by the unique contributions of Fear-Avoidance Beliefs (work) and Depression. CONCLUSION: These findings are consistent with previous models proposing that negative psychological attributes are associated with greater perceptions of pain and disability. Nonetheless, our study indicates that measures of catastrophizing show notable measurement overlap in multivariate models.