Background QRS prolongation and the presence of QRS fragmentation in 12-lead ECG are associated with increased mortality and sudden cardiac death in the long term. In this study we aimed to assess QRS duration and fragmentation in patients with Behcet's disease (BD).Methods A total of 50 patients (mean age 42.7 +/- 12.0 years) previously diagnosed with BD were recruited. In addition, a control group consisting of 50 healthy people (mean age 39.4 +/- 12.5 years) was formed. The longest QRS duration was measured in surface 12-lead ECG and QRS complexes were evaluated in terms of fragmentation. Serum C-reactive protein levels were also obtained.Results QRS duration and corrected QT duration were significantly longer in patients with BD compared with controls (102.75 +/- 11.91 vs. 96.99 +/- 10.91 ms, P=0.007; 438.55 +/- 30.80 vs. 420.23 +/- 28.06 ms, P=0.003, respectively). Fragmented QRS (fQRS) pattern was more common in patients with BD than controls [n=27 (54%) vs. n=16 (32%), P=0.026]. Disease duration was longer in patients with BD with fQRS compared with those without (12.67 +/- 8.68 vs. 7.09 +/- 7.06 years, P=0.010). Furthermore, C-reactive protein level was higher in patients with BD with fQRS compared with those without (6.53 +/- 4.11 vs. 4.97 +/- 6.32 mg/dl, P=0.043). Correlation analysis revealed no association between disease duration and QRS duration (r=0.219, P=0.126).Conclusion QRS duration is greater and fQRS complexes are more frequent in patients with BD. These findings may indicate subclinical cardiac involvement in BD. Given the prognostic significance of ECG parameters, it is reasonable to evaluate patients with BD with prolonged and fQRS complexes more in detail such as late potentials in signal averaged ECG in terms of cardiac involvement.