Immune response are necessary in the body’s defense against tuberculosis. However, the activation of peripheral blood mononuclear cells (PBMCs) in patients with tuberculosis are still unclear. The aim of this study was to determine the pattern of activated monocytes and T lymphocytes in patients with tuberculosis. Twenty-seven healthy controls and 18 patients with newly diagnosed tuberculosis were enrolled. Human leukocyte antigen (HLA)-DR expression in monocytes, CD4 T lymphocytes, and CD8 T lymphocytes was measured using flow cytofluorimetry. CD8 T lymphocyte percentage in PBMCs and circulatory HLA-DR+ CD8 T lymphocytes in patients with tuberculosis were lower than that in controls. HLA-DR expression in HLA-DR+ monocytes and CD4 T lymphocytes in patients with tuberculosis was lower than that in controls. In conclusions, Mycobacterium tuberculosis infection might influence the activation of monocytes as well as CD4 and CD8 T lymphocytes.