Our objective was to analyse economic consequences modifying first line chemotherapy in treatment non small cell lung cancer IIIB-IV. Therefore a cost minimisation has been performed. Resources consumption were collected in a Pneumology department for 21 patients receiving previously mitomycine-ifosfamide-platin and for the 21 first patients receiving vinorelbine-platin, new patients diagnosed during year 2001. Costs were derived from hospital accounting system, economic analysis performed from the hospital and from the health French system points of view. Activity Synthetic Index point decrease of 2.9% per patient in vinorelbine-platin versus mitomycine-ifosfamide-platin, as an increase of 64.6% of hospital drug spending is registered (1,893 Euro versus 1,150 Euro) and an over cost of 15.7% for health French system (14179 Euro versus 12,257 Euro). Whatever the perspective of economic analysis, vinorelbine-platin arm is dominated by the mitomycine-ifosfamide-platin arm.