OBJECTIVES: Psoriasis is a chronic autoimmune disease that affects approximately 2.4‰ of the Taiwanese population. However, little is known about its economic burdens. This study estimated those burdens for patients with psoriasis in Taiwan. METHODS: Patients who had at least one outpatient visit or admission diagnosed with ICD-9-CM code 696.0-1 in the Taiwan National Health Insurance (NHI) claims database during 2006 were identified as psoriasis cases. They were further classified into moderate to severe psoriasis (sPsO) for those who had previously received systemic therapy and mild psoriasis (mPsO) for those who had not. The cases were matched with controls in a 1:4 ratio by age, gender and residential area from a representative NHI dataset. Differences in healthcare utilization between cases and controls were assumed to be attributable to psoriasis. NHI costs were assessed based on a two-part model: a logistic regression to predict the probability of use of services and a generalized linear model to predict utilization for users of services. Out-of-pocket costs, transportation costs, and productivity loss from patients and caregivers were calculated based on face-to-face patient interviews (n=327) during July 2009 to March 2010. All costs were reported in 2009 New Taiwan dollars (1 US$= 31.91 NT$ ). RESULTS: The case-control analysis showed that the NHI cost for patients with sPsO and mPsO was 2.34 times and 1.58 times the cost of controls, respectively. The total cost due to sPsO was NT$56,885 per patient (70%, 18%, and 12% for NHI cost, patient out-of-pocket cost, and productivity loss, respectively). For mPsO, the total cost was NT$28,573 (56%, 33%, and 11% for NHI cost, patient out-of-pocket cost and productivity loss, respectively). Total direct and indirect costs of psoriasis are estimated to be NT$1.80 billion annually. CONCLUSIONS: Psoriasis is associated with a significant economic disease burden in Taiwan.