We aimed to evaluate the relationship of individual periodontal parameters with the severity of Behçet's disease (BD) and attempt to find the correlation between chronic periodontitis and BD. In this study, 74 registered subjects attending Behçet's clinic with BD symptoms were recruited. The diagnosis was based on the criteria presented by the international study group for BD (ISG) and the total clinical severity score was determined for each patient. All individuals underwent clinical examination to assess oral and periodontal status and presence of oral ulcers. Periodontal clinical parameters of bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) and also hygiene index (HI) and decayed, missing, and filled (DMF) teeth were noted and analyzed to assess the correlation with severity of BD. There was no significant correlation between DMF and severity of BD. The strong association was found between periodontal parameters (BOP, PD, and CAL) and the severity of BD (P < 0.001). It seems that relation of BD to oral health is higher up in severe forms of BD and periodontal diseases. Clinical association between the diseases might be due to a common underlying etiopathogenesis of periodontitis and BD.