Objective: To assess the cost-effectiveness of intermittent vs. continuous anti-TNF alpha therapies in chronic plaque psoriasis. Methods: An economic model was constructed to estimate the cost per month in remission for intermittent etanercept 25mg twice weekly (biw) or 50mg biw, continuous adalimumab or continuous infliximab compared with no systemic therapy (NST). Patients considered had chronic plaque psoriasis with both Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) >=10 at baseline, and so would be eligible for anti-TNF alpha treatment under UK guidelines. Remission was defined at patients experiencing an improvement of at least 75% of their baseline PASI. Response rates were taken from registration studies for each agent: maintenance of response with continuous therapy and likelihood of response to intermittent therapy were extrapolated from published studies to a time horizon of ten years using a Markov process. Costs were estimated from a UK payer perspective including drug cost, administration visits and hospital stay for treatment failures. Results: Cost per month in remission for each therapy compared with NST was estimated to be: GBP162 (95% CI: 93-287) for etanercept 25mg biw; GBP418 (337-531) for etanercept 50mg biw; GBP1,867 (1,643-2,136) for infliximab and GBP588 (452-804) for adalimumab. The cost-effectiveness ratios for continuous therapies were sensitive to the criteria used for withdrawal from treatment. The cost-effectiveness ratios for intermittent therapy were sensitive to the duration of treatment interruption achieved and response rate after therapy re-introduction. All regimens were found to be particularly appropriate in psoriasis patients with severe disease at baseline. Conclusion: The model found intermittent treatment with etanercept to be more efficient than continuous treatment with other anti-TNF alpha therapies, as it allows patients to be maintained in response at lower drug cost.