Background and Objectives: Psoriasis is a common, chronic, inflammatory, and hyperproliperative skin disease. It has been known that the infectious agents play a role in triggering and exacerbation of the disease. Periodontal diseases are chronic inflammatory gum diseases initiated by microorganisms in dental plaques. This study intended to determine the role of periodontal diseases, as chronic infective foci in psoriasis. Materials and Methods: A total of 76 patients, who applied to Faculty of Medicine, Department of Dermatology, Inonu University, diagnosed as psoriasis and a control group consisting of 76 dermatologic patients without any systemic disease at similar age and gender were included the study. The dental examinations of the subjects were done by the Community Periodontal Index of Treatment Needs index system, using a periodontal probe. Results: Significant difference was identified between the patients with psoriasis and control group, in terms of CPI (Community Periodontal Index), oral hygiene habits, frequency of tooth brushing and flossing (P = 0.01, P = 0.001, P = 0.01, P = 0.05, respectively). A positive correlation between the severities of psoriasis and dental disease was determined, but this difference was not statistically significant (P = 0.204). Conclusion: The periodontal disease may affect psoriasis as a chronic infectious focus and probably through proinflammatory cytokines. In order to clarify the exact role of periodontal disease in psoriasis, the issue should be studied in larger series with serum cytokine levels.