Objectives. Using the transactional model of stress and coping, the present study investigated whether specific coping resources act as buffers of the relationship between perceived stress and psychological well-being among rheumatoid arthritis (RA) patients. Design. A longitudinal observational study was carried out with assessments at baseline, 6 months and 1 year. Methods. Measures of perceived stress, coping resources (optimism/pessimism, social support and explicit active coping strategies) and psychological well-being (anxiety, depression and life satisfaction) were completed by 134 RA patients. Demographics, RA duration, pain, fatigue, functional disability, antidepressant use and physical comorbidities were recorded and statistically controlled for. Results. Perceived stress had the strongest relationship with psychological wellbeing at baseline, and affected anxiety after 6 months. Optimism and pessimism predicted psychological well-being across I year. Active behavioural coping buffered an association of stress with depression at baseline, while baseline active cognitive coping buffered the effect of baseline stress on life satisfaction after 6 months. Conclusions. Patients with RA under greater perceived stress who do not use active coping strategies appear to be at risk of psychological comorbidity and may therefore benefit from interventions teaching specific active coping strategies. Larger observational studies and interventions are required to confirm and extend these findings.