e18098 Background: For modern evidence-based medicine, a well defined risk scoring system on survival has important clinical implications for identifying patients with a poor prognosis. The objective of this study was to develop a Montreal Prognostic Score (MPS) based on risk scores of the baseline clinical markers. Methods: A training Cohort (TC) and confirmatory cohort (CC) of patients with non small-cell lung cancer were used to develop a Montreal Prognostic Score (MPS) and were assembled of patients from 3 different oncology centres: Jewish General Hospital in Montreal, Quebec, Canada; the University General Hospital of Heraklion Crete, Greece; and at the University General Hospital of Larissa, Greece. Stage, performance status, smoking status, CRP, Albumin, LDH and WBC from TC were entered in a Cox’s model on survival. Independent prognostic factors (p ≤ 0.1) were assigned a relative risk score by dividing their Proportional Hazard by the lowest one rounding to the closest integer. A 3 risk groups’ regression based total score (MPS) was finally developed by regrouping subgroups of patients with similar median survival. The MPS was tested on the CC. C-statistics was used to test the accuracy of the MPS. Results: 638 pts were included in the study: 314 in the TC and 324 in the CC. Majority of patients were stage 4 adenocarcinomas with good performance status treated with platinum-based chemotherapy. Stage, performance status, CRP, Albumin, LDH and WBC retained independent prognostic value and were used to create the MPS. The MPS predicted 3 well defined risk groups of patients with the following median survival and (95% CI) in months: high risk group (87 patients), 5.0 (4.2—7.0); intermediary risk group (98 patients), 9.6 (8.4—11.9); and low risk group (84 patients) 15.2 (12.4—25.1). When the MPS is applied to CC, the results were replicated for each risk group. Overall the TC had a C-stats of 0.673 (95% CI: 0.668, 0.679) while the CC of 0.702 (95% CI: 0.696, 0.708). Conclusions: We have developed a Montreal Prognostic Score based on stage, performance status and the baseline value of CRP, Albumin, LDH, WBC. This MPS has a high capacity of discriminating survival and might have wide implications in clinical practice and research.