Psoriasis is a chronic relapsing disorder which shows variable clinical features. The long-term clinical study with many patients is important to elucidate the epidemiologic characteristics and clinical features of psoriasis. The purpose of this study was to analyze the epidemiologic characteristics and clinical features of psoriasis in Korean patients. Epidemiologic and clinic data and assessments for severity of extent and activity of psoriasis were collected from the medical records of 5084 patients, who had been newly diagnosed with psoriasis in the Psoriasis Clinic of Seoul National University Hospital between 1982 and 2012. The sex ratio of the psoriasis patients was 1.2:1 (male 54.6%, female 45.4%). The peak age of onset in males was 20s, while it was the teenage years in females. A total of 63.5% of patients developed psoriasis before 30 years of age. Family history of psoriasis was observed in 26.0% of patients. Moderate to severe extent of involvement were more frequently observed in male patients and patients under 30 years of onset age than in females and patients 30 years or over of onset age, respectively. Moderate to severe disease activity were also more frequently presented in male patients, but not in patients under 30 years of onset age. The most common morphological type was nummular (56.7%), followed by large plaque (28.5%) and guttate (8.5%). Nail involvement accompanied in 26.4% of patients. We demonstrated the epidemiologic and clinical characteristics of psoriasis in Korean patients.