Drotrecogin alfa (activated) plus best supportive care appears clinically and cost-effective compared with best supportive care alone, in a UK cohort of severe sepsis patients, and in the subgroup of more severely affected patients with severe sepsis and multiple organ failure. The introduction of drotrecogin alfa (activated) will involve a substantial additional cost to the NHS. The treatment-eligible population in England and Wales may comprise up to 16,570 patients, with an estimated annual drug acquisition cost of over 80 million GBP, excluding VAT. Further research is required on the longer term impact of drotrecogin alfa (activated) on both mortality and morbidity in UK patients with severe sepsis, on the clinical and cost-effectiveness of drotrecogin alfa (activated) in children (under 18 years) with severe sepsis, and on the effect of the timing of dosage and duration of treatment on outcomes in severe sepsis.