Background: The aggravating role of Staphylococcus aureus is well known in atopic dermatitis but has not yet been proven in psoriasis. The role of Staphylococcus aureus superantigens is emphasized in the initiation, maintenance and complications of psoriasis. We investigated the frequency of nasal, axillary, and perineal carriage of Staphylococcus aureus (SA) in patients with psoriasis and its possible influence on the severity of the disease. Methods: one hundred patients with the clinical diagnosis of psoriasis participated in the study. Cultures of the bacterial flora were obtained from the right and left axilla and nasal nares and perineum, inoculated on standard bacterial medium (blood agar), and incubated at 37°C degrees for 48 h. Results: one hundred patients with the clinical diagnosis of psoriasis (42% female and 58% male) comprised the study group. Mean age of the patients was 41.1±17.1 years. About 42 % of the patients carried S. aureus; of these, 32 % were from the nose, 13 % from axilla, and 11% from the perineum. Three patients were carriers in all 3 sites. There was no significant difference in the severity of the disease between the carriers and non-carriers measured by the psoriasis area and severity index (PASI) score. Conclusions: According to our findings, S.aureus carriage in psoriasis had no significant influence on disease severity. It might be relevant for a subgroup of patients only when superantigen productions are found.