A clinical analysis of pleural effusion was done on 100 patients who were between 5 and 67 years old. The etiologic diagnosis of pleural effusion at the time of discharge were pulmonary tuberculosis in 38 cases[38%],pneumonia in 20 cases[20%],lung carcinoma in 16 cases[16%],liver cirrosis in 9 cases[9%],congestive heart failure in 4 cases[4%],nephrosis in 3 cases[3%],Meig,s syndrom in 3 cases[3%].liver abscess 2 cases[2%],pancreatitis in 1 cases[1%] and other metastatic malignancy in 4 cases[4%]. Their chief complaints was chest pain in 89 cases[89%],dyspnea in 74 cases[74%],coughing in 46 cases[46%], fever in 13 cases[13%],weakness in 12 cases[12%] and dizziness in 11 cases[11%].