This study investigated the prevalence of psoriasis and trends in prescription of medications for patients with psoriasis using the Korean National Health Insurance Claims Database from 2006 to 2015. The prevalence of psoriasis and psoriatic arthritis per 10,000 people increased from 47.4 to 61.5 and from 0.04 to 0.23 respectively. The prescription of topical agents was a mean of 73.3%. For systemic agents, prescription of acitretin decreased from 74.8 to 44.5%, methotrexate showed a fluctuation, with a mean of 14.9% and cyclosporine increased from 9.0 to 41.2%. The prescription of biological agents increased sharply from 18 to 1,127 patients. Use of ustekinumab increased from 4.1 to 82.4%; use of infliximab decreased from 20.7 to 6.7% and etanercept decreased from 100 to 6.1%. This study showed an increasing trend in the prevalence of psoriasis. We also reported a rapid increase in the use of biologics in recent years.