OBJECTIVES: Psoriasis is a chronic skin disease that strongly affects quality of life of its patients. In Ecuador, this disease affects 0.59% of the population and is estimated that 650 new patients are diagnosed every year with psoriasis according to the Ecuadorian National Foundation of Psoriasis. Biologic treatments had dramatically changed the therapeutics, outcomes and cost of management of these patients. The aim of this study is to assess the cost-effectiveness of biologic alternatives available in Ecuador to treat moderate to severe psoriasis adult patients from a public payer’s perspective. METHODS: A decision-tree model was developed to simulate the clinical course of patients (18yrs+) treated with etanercept (50mg per week), adalimumab (80 mg on week 0, thereafter 40 mg every 2 weeks) and infliximab (5 mg/kg at weeks 0, 2, 6 and thereafter every 8 weeks)  as first-line therapies, as well as treatment associated costs (2-year timeframe with a 5% annual discount rate). Effectiveness measures were the percentage of patients reaching 75% improvement using the Psoriasis Area and Severity Index (PASI-75) and quality adjusted life years gained (QALY´s). Costs considered included: biologic acquisition costs, concomitant medication, medical follow-up and side effects management. Clinical response of alternatives was extracted from published literature. Unit costs were collected from official Ecuadorian databases (Ministry of Health, National Social Security). RESULTS: After two years, the percentage of patients reaching PASI-75 were 59.1%, 62.1% and 62.4% for adalimumab, etanercept and infliximab respectively (p=0.077, Friedman test). QALY´s associated to each alternative were: 1.50, 1.53 and 1.53, respectively. Expected mean costs per patient were: US$ 66,240 for adalimumab; US$ 39,585 for etanercept and US$ 49,055.6 for Infliximab. These results were supported through probabilistic sensitivity analyses. CONCLUSIONS: In Ecuador, the less expensive therapy to treat moderate to severe adult psoriasis patients would be etanercept.