To obtain a correct diagnosis of tuberculous pleuritis by analysis of pleural effusions with standard diagnostic tools is difficult. Mycobacterium tuberculosis (MTB)-specific enzyme-linked immunosorbent assay (ELISA) or MTB-specific enzyme-linked immunospot assay (ELISpot) on peripheral blood was not useful because the judgment was indeterminate or negative. However, we recently encountered 2 cases in which tuberculous pleuritis was rapidly diagnosed by performing MTB-specific ELISpot on pleural effusion mononuclear cells (PEMCs), because high levels of MTB-specific cells by ELISpot were demonstrated in pleural effusion of patients with tuberculous pleuritis. to analyze MTB-specific T-cells in pleural effusion mononuclear cells by ELISpot is feasible in routine clinical practice and may be useful for a rapid and accurate diagnosis of tuberculous pleuritis.