Background: Cognitive impairment in primary Sjögren’s syndrome (PSS) has been identified in several small studies using self-reported measures.Objectives: To quantify cognitive impairment symptoms in a large cohort of 150 PSS patients compared with controls and to explore the relationship between cognitive impairment with fatigue, pain and mood symptoms.Methods: PSS patients fulfilling the American European Consensus Criteria were recruited from 12 sites in England. They completed the Cognitive Failures Questionnaire (CFQ) as well as measures of mood (Hospital Anxiety and Depression Scale), fatigue (visual analogue scale (VAS)), dryness (VAS) and pain (VAS). CFQ scores were compared with data from controls. Completion of the CFQ yields a possible score between 0 and 100. The higher the score the greater the impairment.Results: One hundred and fifty PSS patients and 198 controls completed the CFQ. Cognitive symptoms were worse in the PSS group (43.7 ± 17.8 vs 35.9 ± 12.9; P <0.001). This difference persisted (P <0.001) following analysis of covariance adjusting for age and gender. There were significant correlations with pain, fatigue, anxiety, depression and subjective dryness scores with CFQ scores. In order to partition the variability in CFQ scores into its component parts, we performed a multiple regression analysis. This confirmed that anxiety was the most important predictor of CFQ scores (P = 0.004).Conclusion: Cognitive symptoms are common in PSS and independently associate with anxiety. Clinicians should give consideration to cognitive failure and anxiety in the management of PSS patients.