Twenty patients with locally advanced or metastatic non-small cell lung cancer entered a study of recombinant human methionyl G-CSF (r-metHuG-CSF) as an adjunct to ifosfamide, cisplatin and etoposide (IPE) regimen. Chemotherapy consisted of three courses of cisplatin 25 mg/m2, ifosfamide 1.5 g/m2 (with uroprotection) and etoposide 100 mg/m2 given on days 1-4 of a 21-day cycle. r-metHuG-CSF, 5 micrograms/kg, was administered subcutaneously from day 5 to day 14. Eighteen out of 20 patients completed the three courses (57 evaluable cycles). Grade 3-4 neutropenia affected 50, 42 and 22% of the patients during cycles 1, 2 and 3, respectively, whereas thrombocytopenia was observed in 25% of the patients throughout the chemotherapy protocol. Haematological toxic events requiring transfusions and/or antibiotics were responsible for 11 unplanned hospitalizations. Among these only three were exclusively devoted to febrile neutropenia care, the remaining eight being mainly required for blood transfusions. There were no deaths during the study duration. Dose reductions were needed in 65% of the patients and chemotherapy was delayed by thrombocytopenia in five patients. The total relative dose intensity was 84%. Eleven (55%) patients responded (one complete and 10 partial responses). Median survival was 9.5 months. We concluded that IPE combination chemotherapy can be administered safely with the support of r-metHuG-CSF inasmuch as neutropenia appears as mild to moderate and manageable. Optimal delivery of chemotherapy is still limited by other toxicities, mainly thrombocytopenia, but the successful relative dose intensity observed herein deserves further studies designed to analyze a dose intensity-survival relationship in non-small cell lung cancer.