OBJECTIVE This study examined care consumption and management costs among patients who received second- or third-line oral erlotinib therapy for non small-cell lung cancer (NSCLC). METHODS The study involved two observational cohorts of NSCLC second- or third-line treated patients. In the first, patients received IV chemotherapy alone (233 patients), while patients in the second cohort, received oral erlotinib (166 patients). Only direct costs were taken into account. The analysis adopted the payer's perspective. RESULTS The treatments lasted a similar length in the second- line setting (respectively 94,5+/-67,5 and 105+/-79,4 days for the IV and erlotinib cohorts) but was significantly longer in the erlotinib cohort during third-line therapy (76.6+/-96.5 versus and 114.4+/-74.5 days, p<0.008). In the erlotinib cohort, there were more women (p=0.023), a higher rate of adenocarcinoma (p=0.0043), a similar rate of conventional hospitalization, but less daycare clinics (p<0.001). The erlotinib cohort received significantly less antiemetic treatment (p<0.0001), erythropoietin stimulating agents (p<0.005) and G-CSF (p<0.001). Monthly management costs per patient in the IV and erlotinib cohorts were respectively 3126 +/-1904 and 2750+/-1450 euros during second-line treatment, and 3026+/-1029 and 2823+/-1490 euros during third-line treatment (no significant difference). These results must be validated by prospective observational studies focusing on quality of life and the time spent in hospital.