OBJECTIVES: To evaluate the cost-utility of ustekinumab versus infliximab and etanercept, the only biologic agents available for psoriasis in Thailand, among adults with moderate-to-severe plaque psoriasis who fail to respond systemic therapies and meet criteria based on the biologic guideline for psoriasis in Thailand. METHODS: The published ‘York psoriasis model’ was modified based on the current treatment algorithm and criteria of biologics use in Thai psoriasis guideline. Short-term trial efficacy data (PASI response) from a published network meta-analysis of RCT was used to model the response of patients to initial treatment. Beyond the initial period, the model extrapolated results up to 10 years with annual risk of treatment withdrawal. The DLQI scores from ustekinumab trials were transposed into utility gain (EQ5D) and applied to PASI response level regardless of the treatment received. Both direct medical cost and non-medical cost including biologic acquisition, monitoring lab tests, outpatient visit, and traveling expense were calculated. The amount of resource consumption was estimated by experts’ opinions and literatures. Cost and outcomes were discounted at 3%. One-way and probabilistic sensitivity analysis was conducted to assess the model robustness. RESULTS: Over the 10-year time horizon, ustekinumab showed the lowest mean annual cost of 507,502 baht followed by etanercept (582,881 baht) and infliximab (585,462 baht) respectively. The mean QALY gain of ustekinumab was higher than etanercept (0.1448 vs. 0.1392) but lower than infliximab (0.1448 vs. 0.1564). Considering the cost-utility ratio, ustekinumab was dominant compared to etanercept and infliximab showed the ICER of 6,719,775 baht/QALY compared to ustekinumab. The probability of cost-effective at threshold of 120,000 baht/QALY remained in favor of ustekinumab at 72.60% and presented at 13.60% for both etanercept and infliximab. CONCLUSIONS: Ustekinumab seems to be more cost-effective than etanercept and infliximab for patients with moderate-to-severe plaque psoriasis following biologic treatment guideline for psoriasis in Thailand.