【Abstract】Objective The effects of tumor infiltrating lymphocytes (TIL) on cellular immunologic function of patients with breast cancer were studied. Methods Twenty five patients with breast cancer were treated by the TIL that were isolated from tissue of tumor. T cell subgroups and natural killer cell (NK cell) activity of peripheral blood, the levels of serum soluble interleukin-2 receptor (sIL-2R) were assayed before and after treatment. Results CD3, CD4, CD4/CD8 and NK cell activity were ascended obviously, and CD8, sIL-2R were descended obviously after the treatment of TIL. Conclusion TIL can enhance the cellular immunologic function of patients with breast cancer.