Objective: To estimate mean costs per event of the most common adverse events (AEs) due to treatment of non-small cell lung cancer (NSCLC) in Mexican patients based on treatment patterns (TP) and resource utilization Methods: Specialists were invited to participate in a Modified Delphi Panel to acknowledge real TP of AEs for patients undergoing NSCLC treatment such as neutropenia (NP), anemia (AN), thrombocytopenia (TC), febrile neutropenia (FN), dyspnea (DS), hypersensitivity (HS), rash (RA), nausea (NS), vomiting (VO), diarrhea (DR), stomatitis (ST), peripheral neuromotor alterations (PNA), anorexia (AX) and interstitial lung disease (ILD). Questionnaire was designed based on experts' opinion and answered by specialists, using a nine level Likert scale in order to obtain consensus for the proposed scenarios. Scenarios included drugs use, percentage of hospitalized patients, hospitalization days and visit to emergency room, and laboratory/cabinet exams. Afterwards, an analysis and controlled feedback with a moderated debate stage took place until consensus achievement (=7 approval-median) for each questionnaire item. Economic analysis was done under the public sector perspective. Unitary costs were obtained from the Mexican Institute of Social Security (Diario Oficial de la Federación, 23-04-07). Results are expressed as AE or its treatment cost in US dollars. Results: Eight oncologists participated in the Panel. Consensus was achieved for all items after the questionnaire's second filling round. Second line treatment for NSCLC cost estimate was $5377.46 (includes four chemotherapy cycles with docetaxel, administration costs and premedication costs). Estimated cost for AEs per event was: RA $112.13, AN $140.50, NS $194.56, VO $243.08, DR $243.64, HS $251.56, NP $495.27, TC $948.00, PNA $1167.02, DS $1807.86, AX $1939.88, ST $2055.82, FN $2527.39, and ILD $5189.02 Conclusion: ILD was the most expensive AE due to NSCLC treatment, while the most costly were those incurring in emergency room visits and/or patient hospitalization.