Lung cancer is most common malignancy and is the first cause of death in Iraq. To assess the progression free survival (PFS), and to describe the role of maintaining pemetrexed drug. Retrospective study conducted in Oncology Teaching Hospital /Medical city complex. The period from January 2014 to June 2017. A total of forty seven patients with non-small cell lung cancer, treated by chemotherapy enrolled. Patients assessed for age, gender, histopathological subtypes, first line chemotherapy protocol and progression free survival. The progression free survival was 18.6 months with (95% Confidence Interval (CI)). The progression free survival for adenocarcinoma and squamous cell carcinoma were 19.6, 9.8(months). The maintenance pemetrexed showed a better Progression free survival than other patients. Patients with adenocarcinoma histology have better Progression free survival than other subtypes