OBJECTIVES: . To evaluate the cost-effectiveness of different sub-cutaneous biologic treatments for severe plaque psoriatic patients in public institutions in Mexico. METHODS: . A Markov model was developed to simulate patients with moderate-to-severe plaque psoriasis.  Biologic therapies compared were ustekinumab 45mg every 12 weeks, adalimumab 40mg every two weeks, and etanercept 50mg twice a week.  Measured by the Psoriasis Area and Severity Index (PASI), clinical response was derived from the latest published meta-analysis.  PASI response was translated into QALYs in two steps: (1) defining the correlation between PASI levels and the Dermatology Life Quality Index (DLQI); and (2) using a formula to predict utility from DLQI score derived from a mapping exercise of the DLQI with the EQ-5D.  The model considered expenditure on drugs, monitoring visits, adverse events and inpatient stays. Costs were obtained from Mexican public institutions.  Health and economic outcomes were estimated over a 10-year time horizon with cycle length of 12 weeks.  Cost and QALYs were discounted at 5% annually. RESULTS: . Etanercept is the least costly treatment in Mexican public institutions followed closely by adalimumab and ustekinumab. Cost-effectiveness analysis shows that adalimumab was an extended dominated strategy by ustekinumab.  The incremental cost-per-QALY of ustekinumab vs etanercept was US$19,542.  CONCLUSIONS: . Considering the GDP per-capita of Mexico in 2010 (US$9,123), and according to the WHO Commission on Macroeconomics and Health, ustekinumab is a cost-effective strategy (≤3xGDP per-capita /QALY gained) vs etanercept, and a more cost-effective strategy vs adalimumab by extended dominance.  Probabilistic sensitivity analysis results did not change the conclusions.