Purpose: To compare the efficiency (the evaluation of efficacy in relation to costs) of three first-line treatment options for advanced non-small cell lung cancer (stage IIIB and IV) used in the Eastern Cooperative Oncology Group (ECOG) study: docetaxel/cisplatin (75/75 mg/m 2 /day, 1 h intravenous (i.v.) infusion of docetaxel), paclitaxel/cisplatin (175/75 mg/m 2 /day, 3 or 24 h i.v. infusion of paclitaxel) and paclitaxel/carboplatin (175/400 or 225/400 mg/m 2 /day, 3 h i.v. infusion of paclitaxel). Methods: The results of the ECOG 1594 phase III clinical trial (Proc. Am. Soc. Clin. Oncol. 19 (2000) 2) demonstrated equivalent efficacy (survival, objective response) between the treatment options. To differentiate between the treatment options, we performed a cost-minimisation analysis, using a pharmacoeconomic model. Results: The average estimated treatment cost per patient (median, 4 cycles) with docetaxel/cisplatin would be 1 067 836 Spanish pesetas (Ptas) (6418 Euros; 5741 US dollars (USD)), 1 365 304 or 1 439 369 Ptas (8205 or 8651 Euros; 7340 or 7738 USD) with paclitaxel/cisplatin (3 or 24 h infusions, respectively), and 1 417 995 or 1 616 784 Ptas (8522 or 9717 Euros; 7623 or 8692 USD) (paclitaxel dose of 175 or 225 mg/m 2 /day, respectively) with paclitaxel/carboplatin. Conclusion: According to our study, the treatment option docetaxel/cisplatin, with equal efficacy, would result in a cost saving of between 297 468 and 548 948 Ptas (1788 and 3299 Euros; 1599 and 2951 USD) per patient treated. This difference is mainly due to the lower treatment cost of docetaxel.