Infliximab (Remicade), a biological disease-modifying antirheumatic drug (DMARD), binds to and inhibits the activity of tumour necrosis factor-alpha, which is thought to play an important role in the pathophysiology of rheumatoid arthritis. Intravenous infliximab plus methotrexate is recommended in patients with rheumatoid arthritis who have not achieved satisfactory disease control with adequate courses of other DMARDs. Pharmacoeconomic analyses have been based on efficacy data from the pivotal placebo-controlled Anti-Tumour Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy (ATTRACT) trial in patients with active, refractory rheumatoid arthritis. Infliximab every 8 weeks plus methotrexate demonstrated rapid and sustainable improvements in clinical response, delayed radiographic progression, and/or improved functional status and health-related QOL compared with placebo plus methotrexate at weeks 30, 54 and 102. In cost-utility analyses of infliximab plus methotrexate conducted from a healthcare payer and/or societal perspective in the US, Europe, Portugal, Sweden and the UK, infliximab 3 mg/kg every 8 weeks plus methotrexate was associated with acceptable (<$US50,000 per discounted QALY gained) cost-utility ratios relative to methotrexate alone in patients with active, refractory rheumatoid arthritis. When only direct costs were considered, the lifetime incremental cost per discounted QALY gained with infliximab plus methotrexate relative to methotrexate alone was $US30,500-38,700 (year of costing 1998 or not reported; treatment duration 54 or 102 weeks or lifelong) in the US and Europe analyses, and euro39 500 (year of costing not reported; lifelong treatment) in the Portuguese analysis. The cost-utility ratios were more favourable when lost productivity costs or the additional benefit of infliximab on radiographic stabilisation were considered. In the Swedish and UK analyses with a 10-year time horizon, infliximab plus methotrexate for 1 or 2 years was associated with cost-utility ratios of euro28 600-56 100 (year of costing not reported) when direct costs were considered, and euro3440-48 200 when direct costs plus loss-of-productivity costs were considered. In conclusion, cost-utility analyses, which were based on modelling of data from the pivotal clinical trial of infliximab plus methotrexate, indicate that infliximab plus methotrexate is associated with acceptable cost-effectiveness ratios (<$US50,000 per discounted QALY gained) relative to methotrexate monotherapy in patients with active rheumatoid arthritis who have not responded to previous methotrexate or other DMARD therapy. The cost effectiveness of infliximab versus other DMARDs is at present unclear, but will be clarified when appropriate data from directly comparative clinical and/or pharmacoeconomic studies become available. In patients in whom adequate courses of other DMARDs have failed to achieve satisfactory disease control, infliximab plus methotrexate may prevent or delay disability, which may produce reductions in nondrug costs that can help offset its acquisition cost.