Introduction: Procalcitonin (PCT) is a marker of the inflammatory response to infection. Despite limited research on PCT in pulmonary TB, it is a poor prognostic marker, when serum PCT is above the normal cut-off point (0.05 ng/ml).But, studies for the characteristics of tuberculous pleurisy (TP) patients, according to serum PCT level, have rarely been reported. So, we evaluated differences between TP patients with serum PCT level below or above the normal cut-off point. Methods: A retrospective analysis was done in 73 patients (PCT＜0.05 ng/ml, n=40 (55%); PCT≥0.05 ng/ml, n=33 (45%)) with TP diagnosis, between January 2010 and December 2012. Results: There were 46 male and 27 female patients with a median age of 46 years. Thirty -one patients (43%) had only isolated pleurisy. Out of 70 patients with culture test, culture for mycobacterium was positive in 17 patients (24%) for pleural fluid and 25 (36%) for spontaneous sputum or bronchial washing specimens. Isoniazid resistance and multi-drug resistance were found in one patient, respectively. In a multiple logistic regression analysis, the patients with above the normal cut-off point had significantly pleurisy with pulmonary involvement (OR, 64.179; 95%CI, 1.95-2117.439, P=0.020), and positive culture for pleural fluid (OR, 27.703; 95%CI, 1.392-551.348, P=0.030). Conclusions: Serum PCT level above the normal cut-off point suggests the pulmonary involvement and positive culture for pleural fluid in TP patients. So, it might aid physicians to decide whether to isolate initially, and to evaluate effusion aggressively, for drug sensitivity test. Introduction: Procalcitonin (PCT) is a marker of the inflammatory response to infection. Despite limited research on PCT in pulmonary TB, it is a poor prognostic marker, when serum PCT is above the normal cut-off point (0.05 ng/ml).But, studies for the characteristics of tuberculous pleurisy (TP) patients, according to serum PCT level, have rarely been reported. So, we evaluated differences between TP patients with serum PCT level below or above the normal cut-off point. Methods: A retrospective analysis was done in 73 patients (PCT＜0.05 ng/ml, n=40 (55%); PCT≥0.05 ng/ml, n=33 (45%)) with TP diagnosis, between January 2010 and December 2012. Results: There were 46 male and 27 female patients with a median age of 46 years. Thirty -one patients (43%) had only isolated pleurisy. Out of 70 patients with culture test, culture for mycobacterium was positive in 17 patients (24%) for pleural fluid and 25 (36%) for spontaneous sputum or bronchial washing specimens. Isoniazid resistance and multi-drug resistance were found in one patient, respectively. In a multiple logistic regression analysis, the patients with above the normal cut-off point had significantly pleurisy with pulmonary involvement (OR, 64.179; 95%CI, 1.95-2117.439, P=0.020), and positive culture for pleural fluid (OR, 27.703; 95%CI, 1.392-551.348, P=0.030). Conclusions: Serum PCT level above the normal cut-off point suggests the pulmonary involvement and positive culture for pleural fluid in TP patients. So, it might aid physicians to decide whether to isolate initially, and to evaluate effusion aggressively, for drug sensitivity test.