P wave dispersion (PWD) is a sign for the prediction of atrial fibrillation (AF). The aim of this study was to assess P wave dispersion and its relation with clinical and echocardiographic parameters in patients with rheumatoid arthritis (RA). Thirty RA patients (mean age 49 +/- 10 years) and 27 healthy controls (mean age 47 +/- 8 years) were included in the study. We performed electrocardiography and Doppler echocardiography on patients and controls. Maximum and minimum P wave duration were obtained from electrocardiographic measurements. PWD defined as the difference between maximum and minimum P wave duration was also calculated. Maximum P wave duration and PWD was higher in RA patients than controls (P = 0.031 and P = 0.001, respectively). However, there was no significant difference in minimum P wave duration between the two groups (P = 0.152). There was significant correlation between PWD and disease duration (r = 0.375, P = 0.009) and isovolumetric relaxation time (r = 0.390, P = 0.006). P wave duration and PWD was found to be higher in RA patients than healthy control subjects. PWD is closely associated with disease duration and left ventricular (LV) diastolic dysfunction.