BACKGROUND: Little is known about the health-economic properties of sequences of biologics agents for the treatment of moderate-to-severe psoriasis. These are available to patients who have failed to achieve therapeutic goals on the traditional systemics such as methotrexate and ciclosporin. OBJECTIVES: To predict the five-year costs and health outcomes associated with different sequences of biologic psoriasis treatments (adalimumab, etanercept, infliximab, and ustekinumab), and to evaluate their cost-effectiveness from a Finnish societal perspective. METHODS: The Psoriasis Area Severity Index (PASI) was chosen as the main efficacy measure and results of a published meta-analysis were re-run to provide relative efficacy of the biologics in the short term. A fully stochastic Markov cohort model was developed that represents patient health in terms of PASI, Dermatology Life Quality Index (DLQI), and quality-adjusted life-years (QALY). Failure to achieve efficacy targets, serious adverse events and other reasons of withdrawal led to switch to the next treatment in the sequence, and eventually methotrexate maintenance. Costs included direct medical and related direct costs as well as productivity losses. Costs and QALYs were discounted at 3% per annum. RESULTS: At a willingness-to-pay threshold of EUR 50,000 per QALY gained, only four of the 60 potential sequences had non-zero probability of being cost-effective. The sequence most likely to be cost-effective was first-line ustekinumab followed by adalimumab followed by maintenance. Its incremental cost-effectiveness ratio (ICER) per QALY gained relative to the cheapest sequence (etanercept followed by adalimumab) was estimated at EUR 8,253. Some modelling assumptions tested in the sensitivity analyses may be influential in driving the results, but others, for example inclusion of an anti-TNF class effect, made little difference. CONCLUSIONS: Using a sequence model of biologic therapies in psoriasis, first-line ustekinumab was found to be cost-effective in the treatment of moderate-to-severe psoriasis in Finland.