Psoriasis is a common inflammatory disease that has a severe impact on quality of life. There is lack of data regarding epidemiological and clinical features of psoriasis patients in Turkey, a country with a population of 76million. The aim of this study was to define the demographic and clinical characteristics, quality of life and treatment patterns of psoriasis patients in Turkey. A cross-sectional observational study was conducted at 40 centers, chosen from geographically diverse locations in Turkey. Patients diagnosed with psoriasis were assessed by investigators who were specialists of dermatology using standardized study questionnaire forms. Dermatology Life Quality Index (DLQI) and EuroQol-5 dimension (EQ-5D) forms were also filled out by each patient. 3971 psoriasis patients were included in this study. 24.2% of plaque psoriasis patients had moderate to severe psoriasis (Psoriasis Area and Severity Index, 10). Mean DLQI was 7.03 +/- 6.02; quality of life was moderately, severely or very severely affected in 49.2% of patients. The most severely affected component of EQ-5D was anxiety/depression. Among all patients, 22.9% were not receiving any treatment, 39.8% were receiving only topical treatment, 11.5% were on phototherapy, 26.1%, were taking conventional systemic agents and 4.1% were on a biologic treatment. 31.3% of psoriasis patients with moderate to severe disease were treated with only topical agents and only 30.5% of moderate to severe psoriasis patients were receiving systemic therapy. Moderate to severe psoriasis has a considerable impact on quality of life. Treatment in Turkey of patients with moderate to severe psoriasis is insufficient.