Background and Design:Behçet's disease (BD) is an important cause of morbidity and mortality. Recurrent aphthous stomatitis (RAS) is a condition affecting oral health-related quality of life (QoL). In this study, we aimed to evaluate QoL of BD patients by using the Behçet's disease quality of life instrument (BDQLI) and to compare the QoL of patients with BD with that of patients with RAS and healthy controls. Materials and Methods: Forty patients with BD and 40 patients with RAS and 40 healthy subjects with similar sociodemographic characteristics were included in the study. We used the BDQLI to evaluate QoL of patients with BD and the Dermatology-specific quality of life instrument for comparison of QqL between patients with BD and RAS. 36-Item Short Form Health Survey and clinical data form were applied in all participants. The results were analyzed statistically. The power of the study was 99%. Results: QoL of patients with BD were lower than that of healthy controls. It was observed that patients with BD had decreased physical functions, impaired perception of pain and poor general health (p<0.001, p=0.001, p=0.016, <0.001). Physical functions were decreased and perception of general heath was worse in patients with RAS compared to healthy controls (p=0.018, p=0.021). There was no difference in