ABSTRACT Introduction: Lung cancer is most common cause of cancer-related mortality worldwide. Non-small-cell lung carcinoma (NSCLC) is disease with very low 5-year relative survival rate. For patients with non-small cell lung cancer, roles of current treatments are to prolong survival time and to improve quality of life. Aim: The aim of the work was to compare values of Glasgow Prognostic Score (GPS) before application of the chemotherapy medication with response to chemotherapy and toxic side effects associated with chemotherapy in patients treated with cisplatin-etopozid (PE) and cisplatin-gemcitabin (PG) in stages IIIb and IV of NSCLC. Testing role of Glasgow Prognostic Score as a possible predictor of response to therapy and toxic side effects of chemotherapeutic protocol was another aim of this work. Patients and methods: This prospective study included 60 patients in stages IIIb or IV of NSCLC, with ECOG ≤ 2. The patients were divided in two groups. First group contained 30 patients treated with chemotherapeutic protocol using cisplatin-etopozid (PE), and the same number of patients in the second group were treated with cisplatin-gemcitabin (PG). Results: Glasgow Prognostic Score (GPS) evaluation before the chemotherapy inclusion showed values of 1 (43.30:53.30), then 2 (40.00:36.70) and the lowest 0 (16.70:10.00) which supports the pathological values of GPS in developed lung cancer, i.e. most patients had pathological GPS value in both protocols (83.30:90.00). Monitoring of toxic side effects and response to chemotherapy was done after each cycle of treatment. Discussion: Results of this study revealed importance of GPS in selection of patients for treatment with chemotherapy. Patients with lower values of GPS treated using PE chemotherapeutic protocol had weaker response to therapy. Conclusion: Coefficient of correlation for therapy response in both chemotherapeutic protocol, compared with values of GPS before treatment, were not statistically significant, therefore GPS cannot be considered as a predictor of therapeutic on chemotherapy.