Objectives: Pain is a major factor in health quality in Sjögren's syndrome (SS), but little is known about the factors that contribute to pain severity. Because pain perception has been linked to catastrophizing in other diseases, we assessed subjects with primary SS (pSS) to explore a possible link between pain, illness appraisal, and catastrophizing. Method: A total of 92 subjects who met American-European consensus criteria for the diagnosis of pSS completed a questionnaire that included health history, medication use, illness perceptions, pain severity, mood, fatigue, pain anxiety, and pain catastrophizing. Linear regression was used to test the effect of each variable on pain severity. Multivariate models were constructed using backwards elimination to assess the significant predictors of pain severity. Results: From linear regression analysis, catastrophizing was more strongly predictive of pain severity than age, fatigue, depression, or anxiety in both seropositive and seronegative pSS patients. In the multivariate model identified using backwards selection, four variables (pain catastrophizing, fibromyalgia status, serological status, and the conviction that illness would have severe consequences) predicted 55% of the variance in pain severity. Conclusions: Pain catastrophizing was a significant predictor of pain severity in both seropositive and seronegative pSS patients. This study suggests that behavioural interventions designed to reduce pain catastrophizing and negative appraisal of illness could be of benefit in pSS patients. Research is needed to test the effect of psycho-educational therapies on key patient-reported outcomes, particularly pain, depression, and fatigue, in pSS.