The aim of this study was to assess the effect of secondary Sjögren's syndrome (SjS) on QT dispersion and corrected QT dispersion in patients with rheumatoid arthritis (RA). We performed electrocardiography and Doppler echocardiography on 58 patients with RA whom we divided into two groups according to the presence of secondary SjS, and on 29 healthy controls. All patients revealed significantly longer QT dispersion and corrected QT dispersion values ( P< 0.05). Diastolic function variables were significantly different in all patients compared to controls. QT dispersion and corrected QT dispersion values were significantly longer in RA patients with secondary SjS than in those without. We concluded that secondary SjS could be a cardiovascular risk factor contributing to the well documented cardiovascular disease in RA patients.