The combination of cisplatin and ifosfamide on day 1 plus vinorelbine on day 1 and 8, every 3 weeks, has demostrated a high response rate and acceptable toxicities in advanced NSCLC patients. The present study was designed to analyse the feasibility and toxicity of a similar regimen in which vinorelbine was administered on a weekly basis in advanced NSCLC patients. The scheme consisted of cisplatin 80 mg/sqm, Ifosfamide 3 gr/sqm on day 1, Vinorelbine 25 mg/sqm on days 1,8,15, every 21 days. The dose of vinorelbine on day 8 and 15 was modified according to the absolute neutrophil count. Patients who experienced grade 3-4 neutropenia received G-CSF (300 micrograms total dose subcutaneously) from days 10 to 13 and from 17 to 20 of each subsequent course. Twelve patients were treated and forty-six courses were evaluable for toxicity. Grade 3-4 neutropenia was observed in 63% of the courses; 3 episodes of febrile neutropenia were recorded. Vinorelbine on day 15 was omitted in 52% of the courses and was given at 75% and 50% of the planned dose in 11% and 4.3% respectively; G-CSF was administered in 65.2% of the courses. This scheme is not feasible because of the high incidence of grade 3-4 neutropenia. In spite of G-CSF, the dose of vinorelbine on day 15 was omitted or reduced in the majority of the cycles.