Docetaxel (75 mg m(-2) 3-weekly) is standard second-line treatment in advanced non-small-cell lung cancer (NSCLC) with significant toxicity. To verify whether a weekly schedule (33.3 mg m(-2) for 6 weeks) improved quality of life (QoL), a phase III study was performed with 220 advanced NSCLC patients, < or =75 years, ECOG PS < or =2. QoL was assessed by EORTC questionnaires and the Daily Diary Card (DDC). No difference was found in global QoL scores at 3 weeks. Pain, cough and hair loss significantly favoured the weekly schedule, while diarrhoea was worse. DDC analysis showed that loss of appetite and overall condition were significantly worse in the 3-week arm in the first week, while nausea and loss of appetite were more severe in the weekly arm in the third week. Response rate and survival were similar, hazard ratio of death in the weekly arm being 1.04 (95% CI 0.77-1.39). A 3-weekly docetaxel was more toxic for leukopenia, neutropenia, febrile neutropenia and hair loss; any grade 3-4 haematologic toxicity was significantly more frequent in the standard arm (25 vs 6%). The weekly schedule could be preferred for patients candidate to receive docetaxel as second-line treatment for advanced NSCLC, because of some QoL advantages, lower toxicity and no evidence of strikingly different effect on survival.