OBJECTIVES: Non-small cell lung cancer (NSCLC) is a leading cause of morbidity and mortality throughout Europe. Clinical evidence in favour of gemcitabine/platinum combination therapy as first-line treatment in advanced NSCLC has already been accepted. The present study reports the methods and results of an analysis comparing the chemotherapy acquisition and administration costs of a 28-day gemcitabine/cisplatin regimen (GEM/CIS) with a 28-day gemcitabine/carboplatin regimen (GEM/CAR). METHODS: The analysis involved quantification and costing of medical resource utilisation arising solely from planned differences in the treatment regimens. Clinical outcomes achieved by the two regimens were assumed to be equivalent. A simple micro-costing of the costs associated with chemotherapy administration incorporated a fixed cost per administration plus a variable cost depending on the duration of the intravenous infusion of the therapy being administered. Threshold analysis derived the opportunity cost of patient time spent in the chemotherapy unit at which GEM/CAR becomes the cost-minimising treatment regimen. RESULTS: Patients treated with GEM/CIS had a total cost of €5884 in France and £5474 in the UK. The costs of GEM/CAR were €6607 and £5599 in France and the UK respectively. In both countries chemotherapy acquisition costs were higher, and administration costs lower for patients treated with GEM/CAR. GEM/CAR became the cost-minimising treatment when the opportunity cost of time spent in the chemotherapy unit was approximately €38.63 per hour in France or £15.83 in the UK. CONCLUSIONS: Drug administration costs of carboplatin compared to cisplatin do not offset the additional chemotherapy costs. However, financial considerations may not be paramount in the decision to treat patients with GEM/CAR as opposed to GEM/CIS. Patient and physician preference for a more convenient mode of administration are clearly important factors.