e19157 Background: Comorbidity may influence prognosis in lung cancer, affect performance status (PS) of patients as well as complicate treatment. The present study examines usage and outcome of chemotherapy (CT) for advanced-stage lung cancer, and focuses on the role of comorbidity. Methods: Patients with advanced-stage lung cancer were identified in the Danish Lung Cancer Registry. A total of 22,999 patients with non-resectable, advanced-stage lung cancer were identified. Data on stage, PS, Charlson comorbidity score (ChS), age, histology and type of first treatment (if any) were avaliable. First treatment was categorized as chemotherapy (n=7,346), chemo-radiotherapy (2,636), radiotherapy (n=4,155) or no therapy (n=8,862). Survival was examined separately for 0-1 year and 1-5 years, and further distinction was made between metastatic and non-metastatic lung cancer. Data are presented for the subgroup of patients receiving chemotherapy as first treatment only. All estimates are derived from logistic regression model adjusting for the effect of performance status, pulmonary function and histological type, except for usage where models included same variables plus stage. Results: Use of chemotherapy was less frequent for more comorbid patients (OR 0.86, 0.64, 0.56 for Charlson score 1, 2, 3+ respectively compared to no comorbidity). Older patients and men were less likely to receive CT. For patients receiving CT as first treatment for non-metastatic lung cancer, survival in the first year was slightly worse for those with co-morbidity (HR 0-1year, non metastatic =0.91, 0.92, 0.87 for ChS 1,2,3+ respectively). For 1-5years and for metastatic lung cancer no correlation between comorbidity and survival was noted. In contrast, PS and sex was strongly associated with survival. Conclusions: With increasing co morbidity, chemotherapy was used less often. Comorbidity is not an important prognostic factor in advanced lung cancer treated with chemotherapy. However, sex and especially performance status remain as strong prognostic factors in this patient group.