OBJECTIVES: To evaluate the costs in Spain of treating advanced non-small-cell lung cancer (NSCLC) with gemcitabine plus cisplatin (Gem/Cis) in comparison with other platinum-based combination chemotherapy regimens, and to compare the findings with previously published cost analyses. METHODS: A retrospective economic analysis was conducted based on medical resource utilisation in a randomised controlled trial (Scagliotti et al. 2002), which found that Gem/Cis demonstrated comparable efficacy to paclitaxel/carboplatin (Pac/Carbo) and vinorelbine/cisplatin (Vin/Cis) regimens in 612 patients with advanced NSCLC. Treatment costs were compared across four main resource categories: chemotherapy acquisition, drug administration, hospitalisation episodes, and other medical resources. Spanish healthcare unit costs were drawn from published literature and public sources. Results were compared with those published by Schiller et al. (2004). RESULTS: The mean total treatment-related costs of Gem/Cis were 5,578€ per patient, which was lower than those seen with Pac/Carbo (11,541€) or Vin/Cis (6,084€). Chemotherapy acquisition was the major cost driver for Gem/Cis (63% of total costs) and Pac/Carbo (90% of total costs), but other component costs, especially hospitalisations, were considerable for the Vin/Cis regimen (36% of total costs). The total costs per patient are comparable to those reported for Spain by Schiller et al. (2004) with calculations based on Comella et al. (2000) (Gem/Cis 4072€; Vin/Cis 4899€) and Schiller et al. (2002) (Gem/Cis 5082€; Pac/Carbo 8,40€), trials employing different dosing schedules. CONCLUSIONS: Cost-minimisation analyses based on chemotherapy and resource utilisation in randomised controlled clinical trials demonstrate that Gem/Cis has lower total treatment costs from the perspective of the Spanish national health system than Pac/Carbo and Vin/Cis for the treatment of advanced NSCLC.