Background: About 80% to 85% of lung cancers are non-small cell lung cancer (NSCLC), which are believed to secrete mediators that may lead to disorders in the immune system and tumor immune surveillance. This disorder may include dysfunction in CD8⁺ T cells and NK cells, which play critical role in fighting against cancer. Aim: Evaluate the impact of lung cancer on the numbers and function of CD8⁺ T cells, NK and NK T cells as well as the inflammatory milieu. Materials and Methods: Peripheral blood samples were collected from healthy volunteers (n=5) and early diagnosed lung cancer patients (NSCLCs; n=5). The numbers of CD8⁺ T cells, NK cells and NK T cells were analyzed by flow cytometry after staining with the relevant antibodies. Plasma was prepared from the blood to measure the proinflammatory cytokines and chemokines by Lumiex® protein array. Results: Compared to healthy controls, lung cancer patients showed significant decrease in numbers of CD8⁺ T cells and NK cells. NK cells showed considerable reduction in their expression levels of the cytolytic molecule granzyme-B. Marked higher levels of IL-1 and CCL2 was detected in the plasma of lung cancer patients as compared to healthy controls. Conclusion: Early diagnosed lung cancer patients showed dysfunction not only in the numbers of cytolytic immune cells but also their function that correlated with inflammatory microenvironment.